The £20 million southern entrance to Leeds Station has been officially opened, serving new residential and commercial developments alongside the River Aire. It’s expected that one-in-five passengers – about 20,000 people daily – will use it.
The construction process has been complex, both in terms of logistics and engineering. Materials had to be brought in by barge from a holding area quarter-of-a-mile away and then lifted into position by a tower crane located in a service yard behind an apartment block.
Yorkshire is currently the focus of a significant rail investment programme. This will bring new trains, additional services and the return of three former stations. At Low Moor, works have been ongoing since August, but the project team has had to deal with years of fly tipping, a leaking high-pressure gas main and disused mine workings.
Low Moor is likely to welcome its first passengers in the summer. Apperley Bridge Station, on the commuter route between Leeds and Bradford Forster Square, opened in December and another, at Kirkstall Forge, is close to completion.
Let’s set the scene. The rain was stair-rodding it and the wind was at gale force. The normally majestic backdrop of Pen-y-Ghent was lost somewhere in the grey murk and the land surrounding the work site was standing in water.
‘Go and get me some good pictures of the new sidings project at Helwith Bridge,’ the Production Editor had said … ‘And make sure it’s sunny!’
Well, what did he really expect? This was the Settle and Carlisle line after all!
Wind and water or not, the construction activity continued unabated. These seasonably dampened works were part of a £6 million scheme to once again connect Tarmac’s Arcow quarry near Horton-in-Ribblesdale with the national rail network. Funded by Tarmac Holdings Ltd, the scheme has been managed by Network Rail, with design and implementation work being awarded to Story Contracting (civils and track work) and Babcock Rail (signalling).
Arcow and its near-neighbour Dry Rigg quarry, both owned by Tarmac, have been worked under various ownerships for more than a century and there was a previous rail connection here. The then Ribblesdale Lime Company’s extensive sidings were controlled by the adjacent Helwith Bridge signal box. Closure of the sidings and signal box came in 1969 and road haulage has been in operation since then. Now, as you read this article, GB Railfreight is set to haul the first trainload of road stone out of Arcow quarry in fifty years.
Earthworks
Providing the new rail connection has been no small achievement. To all intents and purposes, a 750-yard stretch of entirely new railway has been built, ending in a siding fan within the Arcow quarry stocking ground. Indeed, this new line even has its own Engineering Line Reference – AQL (Arcow Quarry Line).
The previous sidings formation was deemed unsuitable for today’s requirements, particularly with regard to the curvature of the approach track. A new trailing connection has therefore been made with the Settle and Carlisle line, about 400 yards north of the old connection.
The new approach track leaves the Down main line on a falling gradient of 1 in 100, runs parallel with it for a short distance and then curves away across boggy agricultural land. In doing so, it is carried on a new embankment that reaches a maximum height of 3.5 metres before it meets the 20-metre high screening bund at the south end of the quarry site.
Constructed 25 years ago to satisfy Yorkshire Dales National Park (YDNP) planning conditions, the screening bund is built on a truly massive scale. Cutting a V-notch through it for the new railway has required the removal of 60,000 tonnes of material. Although unsuitable for use on the embankment, the excavated quarry waste has nevertheless been put to good use within the quarry site to form new roadways.
Raising the new embankment has required 26,000 tonnes of material that, in order to minimise transportation, was sourced entirely from within the quarry. The earthwork design was therefore tailored to suit this available material. Of all the rock materials used, only the track ballast, sourced from Shap quarry, had to be transported to site.
Settled
Not surprisingly, the construction of a substantial embankment over soft ground can present some problems. George Stephenson achieved success at Chat Moss by ‘floating’ his railway on bound bundles of heather and brushwood. But, taking a more modern approach, the solution adopted at Arcow quarry has been to surcharge the earthwork with additional material in order to hasten the settlement process. The technique used was more sophisticated than just depositing lots of material and hoping for the best, as Chris Sidwell, project manager for Story Contracting, outlined.
“We needed to avoid slippage and rotation at the embankment toe, which could occur if we added material too quickly,” Chris explained. “Although a geogrid was incorporated into the base of the embankment to provide stability, a crucial factor was the height of the water table. As material was added to the embankment, the increased downward force produced an increase in the ground water pressure, causing the water table to rise. It was this that could destabilise the embankment.
“Accurate measurement of the ground water pressure was vital. The technique, provided for us by Central Alliance, involved drilling boreholes down to between four and seven metres below ground level. Vibrating wire piezometers were lowered into the holes to the level of the natural water table, where they were then encased in sand cells.”
These devices have a flexible diaphragm that responds to external pressure changes. A wire attached to the diaphragm is tensioned and can be made to resonate by an electrical coil. The resonant frequency of the wire can be measured. In other words, the resonant frequency of the wire changes in sympathy with the external pressure acting on the sensor. The pressure measurements at Arcow were recorded by data loggers at three-minute intervals to produce a plot of pressure against time.
Chris continued: “As the embankment material was added and compacted, we could see a sharp rise in the water table pressure, which then gradually subsided.
When the pressure slowly returned to its former level we knew we could safely add more material. Thus the ground water pressure, and therefore water table level, when plotted against time, formed a characteristic saw tooth graph.”
The eventual objective was to add about one metre of additional material to the embankment, which was then allowed to settle for 28 days. During this time, the embankment level dropped by approximately 0.1 metres, with the rate of settlement decreasing as time passed. By studying the characteristics of this phase in the settlement process, the level of the embankment, with its surcharge of material removed, could be predicted into the future. When the ongoing settlement rate was known to be within manageable limits, the track could be laid.
During the embankment forming process, the level of the settlement was measured by means of rod and plate markers, the plate being installed at the original ground level. Future settlement at rail level will be monitored for some time by means of surface settlement markers fitted at cess level.
Deadline
The scheme project manager for Network Rail was Joelle Caldarelli, who was pleased to point out that the project had progressed from the planning stage to completion in a little over a year. “Physical work started on site in the summer, with the project time working towards the critical milestone of a 78-hour line closure, scheduled to take place between 23 and 27 October. As it was, to the great credit of Story Contracting and Babcock Rail, the vital preparatory works were completed one week ahead of that schedule.” The crucial blockade was necessary for the switches and crossings to be installed at the tie in.
Another aspect of the project that Joelle is happy with is the footbridge that carries a public footpath across the access line adjacent to the quarry bund. She explained: “At just the right moment, a lattice footbridge became available to us after its removal from a site in Camden.” Following complete refurbishment, the bridge, which has an eight metre span, was installed onto stone-faced abutments and now provides an excellent vantage point from which to view the sidings. “It’s nice to be able to reuse a beautiful piece of Victorian engineering in this way,” said Joelle.
But the project wasn’t without its challenges, with one issue being the discovery of Great Crested Newts. These protected, but seemingly omnipresent, amphibians were found to inhabit a natural dewpond adjacent to the route of the access line. Bowland Ecology installed newt fencing around the work site and a temporary dewpond was created nearby to relocate the captured amphibians. The newts will be returned to their original pond upon final completion of the landscaping.
Value
Within the quarry site, no substantial earthworks were required. The development has two sidings and a 135 metre long loading ramp has been constructed adjacent to siding number 1. YDNP planning conditions have dictated that a dust suppression facility should be provided. Water misting stanchions have therefore been installed between sidings 1 and 2. The water misting starts automatically when the presence of a front-loading shovel is detected.
Planning restrictions also limit the operating hours of both the Arcow and Dry Rigg quarries and restrict the maximum number of trains leaving the quarry to five per week.
Aggregate from Dry Rigg quarry will be hauled the short distance to Arcow quarry by road for onward transportation by rail. Each quarry produces road stone that is nationally important. It is a form of grit stone that has a high PSV (polished stone value), which makes it suitable for use on motorways, either as coated stone (within asphalt) or as a top dressing. The properties of the Arcow and Dry Rigg products are slightly different, so the two materials will be transported in separate rail wagons.
Each siding is able to accommodate up to eight 75-tonne wagons, so initially the maximum train weight will be 1,200-tonnes. It is estimated that this will remove 16,000 lorry journeys each year from the Yorkshire Dales National Park.
Signals
GB Railfreight will haul these loads using Class 66 locomotives and VTG-leased HYA bottom- discharging bogie hopper wagons. The destinations will be Hunslet East, Agecroft and Bredbury. The Arcow sidings connect with the Down (northbound) line, meaning that all trains will travel to Blea Moor before heading south.
To allow the locomotive to run round at Blea Moor, Babcock Rail has installed signalling enhancements there. It is now possible for Down trains to directly access the Up goods loop at Blea Moor. Previously this was not a signalled move.
Noticeable is the replacement of signal BM29, formally a running shunt signal, by a Dorman ‘lightweight’ three-aspect colour light signal, complete with position light junction indicator (feather), plus a ‘cats eyes’ subsidiary signal and route indicator.
The main line and trap points at Arcow are controlled from a local ground frame. Rather than clunking levers and point rodding, power operation has been favoured, making use of SPX Rail Systems in- bearer Clamp Locks. Control is from a shunter’s panel that is released from the lever frame at Settle Junction signal box.
Because the new points are located within an Intermediate Block Section that uses axle counters (issue 67, May 2010), and because of the need to shunt trains ‘inside’ at Arcow quarry, additional track circuits have been added into the axle counter section.
As part of the new signalling arrangements, Babcock Rail has needed to alter the mechanical lever frame interlocking at Settle Junction and Blea Moor signal boxes – something of a dying art these days.
Win-win
It’s a symptom of the times that many freight paths on the Settle and Carlisle route are now largely unfilled. Whereas once they were commonplace, you could wait a long time today to see a coal train breasting Ais Gill summit. Having a new freight flow on the line is therefore good news indeed and GB Railfreight was very pleased to sign a new contract with Tarmac.
The residents of Settle and the Dales aren’t arguing with this development either. Even though there are some planning restrictions on Tarmac’s operations at Arcow and Dry Rigg, transferring much of the aggregate output to rail will allow these quarries to operate at greater efficiency.
It’s hard to see a down side. Maybe we should all be singing along to Errol Brown’s classic hit, ‘Everyone’s A Winner.’ Come to think of it, some hot chocolate wouldn’t have gone amiss during our site visit!
For those of us afflicted by a get-on-with-it culture and a lifestyle built on thrift, there is something rather uncomfortable about HS2. Back in the autumn of 1890, visionary industrialist Sir Edward Watkin presented to Parliament his proposals for an ambitious new main line – 92 miles in length – connecting the coal-rich North Midlands with a terminus at London Marylebone. Engineered for speed, it boasted a generous loading gauge, curves rarely tighter than one mile in radius, a ruling gradient of 1:176 and just a single level crossing.
Like HS2, opposition to Watkin’s plan was organised and vociferous, not least from the companies whose lucrative business he was intent on partly pilfering. But nothing got in his way – neither nature nor vested interests. For two miles, the line burrowed through sandstone to reach a station in the heart of Nottingham and, to placate an enraged MCC, a route was cut-and-covered under the Nursery End of Lords Cricket Ground.
The Great Central’s London Extension still stands out as a truly exceptional railway, delivered with limited mechanical assistance for the 2016 equivalent of around £1.2 billion. And less than eight years after the plans’ ink had dried, mineral traffic started to repay that investment.
Out of town
The Labour government established HS2 Ltd in 2009 and, without one sod being turned, expenditure reached almost £700 million in its first six years. That is – like it or not – the nature of life in the 21st century, costs being launched skywards by the jet engines of regulation, consultation, uncertainty, bickering, froth and newts.
But worthy of even more note than HS2’s current price tag (which exceeds the combined Gross Domestic Product of Latvia and Estonia) are the compromises that £55.7 billion bring with it. In Birmingham, the line stops tantalisingly short of the connective hub at New Street whilst those visiting the East Midlands’ will alight in a residential no-man’s land between Nottingham and Derby. As for Sheffield – England’s fourth most-populous city – serving it will be a station four miles away. Yes, HS2 offers raw speed but with the slightest whiff of EasyJet.
It should of course be recognised that HS2’s Leeds and Manchester legs – known as Phase Two – won’t be nailed down until the autumn, including their respective station sites. There are apparently no dissenters to the East Midlands Hub at Toton, however Sheffield’s political and business leaders have, from the outset, made clear their opposition to a station next to the retail nirvana of Meadowhall Shopping Centre, claiming that it would significantly restrict the potential for growth. Their position has particular resonance in the context of Transport for the North’s objective of radically improving links between city centres.
HS2 asserts that the difficult engineering task of routing the line through Sheffield – instead of around the eastern side of it – would add about £1 billion to the overall project cost. But a study undertaken for the City Council suggests that more than double that amount would accrue in economic benefit from establishing a central station, not to mention 6,500 additional jobs and significant residential development opportunities. Leigh Bramall, the council’s deputy leader, pointed out that “it is absolutely vital to get it right”, recognising that whatever we build now will be with us forever. He could have said “it is absolutely vital to get it done cheaply”, but chose not to.
U-turn if you want to
Those hoping for a change of heart in Sheffield might take comfort from Sir David Higgins’ interim report on HS2’s station in Leeds which tackled a number of issues familiar to the campaigners in South Yorkshire. Under the original plan, trains there would have terminated on New Lane, south of the River Aire and around 330 metres from the new southern entrance to Leeds’ current station. According to the report, whilst this site “fulfilled HS2’s brief”, there was a danger that it would have been “too detached from the existing station and too isolated from the city centre.”
Several negative impacts were identified:
The walking distance of between 5-10 minutes brings difficulties with connectivity and undesirably exposes passengers to the elements (note: also applies in relation to Birmingham New Street)
HS2 services are “too isolated” for those starting their journeys in the city centre (note: also applies to Sheffield)
The absence of a shared HS2/classic concourse could potentially act as a passenger mindset barrier
Regional and local authorities had serious concerns about the proposals, particularly in relation to the quality of the linkage and the City Council’s wider aspirations for a landmark redevelopment on the south side of the River Aire.
Against this background, HS2 Ltd published a report in November 2014, entitled Rebalancing Britain, which recognised the importance of finding a solution that delivered broader connectivity across the Leeds City Region. Four months later, George Osborne launched his Long Term Economic Plan for Yorkshire in which he asked Higgins to reconsider options for Leeds’ new station.
It’s worth noting that, in London and Leeds, HS2 will connect the country’s two biggest financial services centres, as well as helping to create an integrated economic and manufacturing zone of more than ten million people east of the Pennines/Peak District. The Leeds City Region alone contributes 5% of the UK’s annual economic output, amounting to £60 billion. Leeds is already the busiest station in northern England, with passenger numbers expected to increase by 114% over the next 30 years. The Northern Powerhouse and new HS3 trans-Pennine route are likely to fuel that growth. So any redevelopment of Leeds Station had to be built around its likely future role as the region’s connective hub. In other words – just as in Sheffield – getting this wrong would have huge, long-term consequences.
Nature of the challenge
Stakeholder engagement resulted in the emergence of five guiding principles against which all potential options for the new station would be measured. Those principles stipulated that:
the classic and HS2 stations should share a common concourse, accessible from the city centre, South Bank and waterfront
the new station should become an integrated transport hub with improved car and bus access
capacity should be created for a two-thirds increase in services resulting from the Northern Powerhouse and HS3
enough through train paths should be provided to enhance both local and Northern Powerhouse services
the design should reflect the station’s significance as a local, regional and national landmark.
Non starters
Today’s Leeds Station is built on a hill falling south from the city towards the River Aire. Much of it is supported on vaulted brick arches which now host restaurants, shops and exhibition space. Completed in 2002, the station’s last significant redevelopment provided five new platforms (making 17 in total) with improved passenger access, a glass roof, additional tracks on its western approaches and the transfer of signalling control to York. Only two tracks enter from the east side, accommodated on an 1860s viaduct, more than half-a-mile in length.
Coupled with modern urban sprawl, those Victorian structures act as physical constraints to the HS2 station, whilst the need to keep within the project’s overall Phase Two budget ruled out heavy engineering solutions such as tunnelling or double-decking. Despite this, three options were identified for further development and analysis.
The first suffered from broadly the same shortcomings as the original proposal, using the same site on the south side of the river but with slightly better linkage to the classic station. Stakeholders did not regard it as an improvement.
Differing fundamentally, the second option offered an integrated station with HS2’s tracks approaching from the east into platforms on the southern side of the site. This raised the possibility of connections onto the classic network and through services being established as part of the Northern Powerhouse.
However, with no opportunity to extend the station southwards, the impact on capacity would have been considerable. Analysis indicates that, from the west, 53 hourly services will eventually be needed to meet predicted passenger demand into Leeds, but limited platform space would have capped the number at 44. Alongside those serving HS2, room would only have been available for 11 classic platforms; a future requirement for 22 is conceivable. There was also concern that HS2’s easterly approach would constrain capacity for the growth of regional services, negatively affect adjacent heritage and bring operational disruption during the construction period for as long as eight years.
T-junction
HS2’s preferred route into Leeds is along the Aire Valley from Woodlesford, following the corridor of the Castleford/Wakefield Kirkgate line. The original plans show the city’s 900-metre long station stopping short of the river, thus creating the disconnect that so concerned the regional leadership. The third option bridged that gap by bridging the river, joining the existing station at right angles.
Whilst this overcomes many of the problems identified with the initial proposal, it is not without its issues. In partnership with the Environment Agency, assessments will need to be carried out to understand the structure’s impact on ongoing flood alleviation schemes, water quality and river habitat improvement work. It also has the potential to sit uncomfortably alongside the city’s adjacent conservation area and canal wharf, now a thriving public space after years of sympathetic redevelopment. The alignment of the station would also lengthen a dingy 100-metre thoroughfare created by Neville Street passing beneath the existing station – a longstanding cause of concern from a personal safety perspective.
The positives though are overwhelming, resulting in a clear consensus emerging around this option. It provides the shared concourse and easy connectivity considered by stakeholders to be vital, as well as establishing better pedestrian access between the city centre and South Bank regeneration area.
The station’s future capacity is not compromised, with land remaining available on its north side for extra platforms catering for growth in Northern Powerhouse services. There is also the opportunity for through trains to/from HS2 via a link with the Castleford/Wakefield Kirkgate line.
Sauce for the goose
“Quite rightly,” Sir David Higgins asserts, “local and civic leaders made clear their view of the limitations they saw in our original proposal, in particular its failure to connect local, regional and HS2 services and to connect into the existing city centre, and the plans for its expansion.” HS2 should be commended for its willingness to engage with those concerns and come up with something that better fits the bill.
You are though left to wonder what’s different about the East Midlands, Birmingham and Sheffield where all the same shortcomings are evident to some extent. Isn’t direct connectivity to existing major rail hubs key to fully exploiting HS2’s potential? Doesn’t the inherent benefit of high speed – faster end-to-end journey times – rely on stations being right at the heart of major commercial and population centres?
The world comes with compromises, but you’d like to think that £55.7 billion would buy you very few of them. The word did not apparently feature in Sir Edward Watkin’s vocabulary, as his now-redundant tunnels under Nottingham demonstrate. With its transformational potential, HS2 could heal some of the economic wounds inflicted on Sheffield by industrial decline. The city will be keen to enjoy the same persuasive success that Leeds has in securing the right station for its future.
Hic sunt dracones translates from the Latin as ‘here be dragons’. Many believe that it appeared on ancient maps to show the limits of cartographers’ understanding at the time, emphasising the threats from venturing over borders into the unknown. Surprisingly, the words appear on maybe just the one globe of around 1507, but that doesn’t stop them from being a neat way of saying, “Proceed at your peril. You really don’t know what you’re getting into!”
This notion of monsters and many-headed hydrae (or maybe its hydras) lurking to devour the unwary would have influenced the way that the navigators of old ventured beyond their comfort zone.
Of course, in fact, monsters there were few. Hydrae were mono-capitated if they existed at all. Life was not as complicated or terrifying as first thought.
Over the boundary
These days, some of our minor railway colleagues, particularly on the signalling and operating side, gaze at working drawings that cover not only their territory but also that of the main line railways. They look over their boundaries using maps which, whilst having a deal of technical detail, also have the implied ‘hic sunt dracones’.
Some have ventured into the unknown and all report that there really are dragons, monsters and many-headed hydrae too. It’s all true!
But the monsters and hydrae are benign, a complete change from ancient days (that’s about 20 years ago). It doesn’t mean that you don’t have to be very careful. They can be upset and can prevent any incursions onto their territory.
The Minor Railway Section of the IRSE held its bi-annual technical workshop in a room above the museum of the Severn Valley Railway at Kidderminster recently. Ably choreographed by Major Ian Hughes of Green Dragon Rail, no relation to those mentioned above, the event was sponsored by Signal Aspects Ltd. (the company set up by our very own writer Stuart Marsh). Several of the papers presented dealt with the tricky issue of running trains from Minor Railways onto the mainline network. These movements are no longer just the occasional locomotive and stock movement, they are full blown, regular timetabled moves. Minor railway trains have, in several locations, been integrated into the mainline timetable.
Onto the mainline network
Take, for example, the Swanage branch. This was shut in 1972, the metals removed and the rail link from Wareham to Swanage effectively destroyed. Stirling efforts by volunteers with political support brought a restored railway closer and closer to the main line with the obvious ambition to reinstate services to the coast. Michael Walshaw described the negotiations and the resultant signalling arrangements that closed the gap.
The North Yorkshire Moors Railway harboured (!) an ambition to run all the way from Pickering to Whitby, joining the national network at Grosmont. It was challenging and Charles Weightman gave an account of the various complex stages of the scheme to expand the facilities at Whitby station and Grosmont East to allow the NYMR to run five trains a day to the coastal resort.
There was an interesting twist to the tale with a paper presented by Ronald Bresser of Movares who outlined almost parallel issues in the big container depots in the Netherlands. These are private railways that have multiple movements to and from the main line railways. But these are not just the odd few coaches; they are long, very long freight trains. Dwell too long sorting out acceptance on either side of the border and valuable minutes tick by.
The Ffestiniog Railway and the Welsh Highland Railway had an operating issue at Porthmadog station which they both share. The notions of borders and dragons is far less pronounced here, but there was still the problem of a train from one railway stitching up moves for the other operator. Tim Prent gave an account of the thought processes that went into an ambitious project to widen their infrastructure to give everyone elbow room to run their services. It was a ‘chunky’ scheme which didn’t hit the headlines at the time which is why we’ve given it a bit of exposure here.
Heroic restorations
The minor railway guys are amazing when it comes to rescuing bits of kit. Dominic Beglin of Peak Rail showed a pallet load of what appeared, to the uninitiated, to be ‘parts destined for the furnace’. The result of a clear out by the National Railway Museum, these turned out to be priceless (maybe an exaggeration) components for a wire operated turnover lever frame. There was a tale of missing parts, sketchy records, trips to Vietnam and just sheer determination to make something work, which it did.
Similar treatment was given to a monster signal gantry that had had a chequered career. It was moved from Scarborough to its new location at Grosmont having been shorted, repaired and fitted with carefully refurbished timberwork described by Craig Donald.
Award
In the closing stages of the workshop, the cacophony of kids of all ages knocking seven bells out of the exhibits in the museum below had begun to subside. The sun had come out after a morning of dire weather that had driven everyone indoors from the platforms. This relative calm allowed Mike Tyrell to deliver his citation for the MRS volunteer of the year. The deserving recipient, Geoff Harris of the Bluebell Railway, benefited from a range of goodies and a wildly unstable and heavy trophy in the form of a token staff from the Bluebell Railway.
The success of this workshop, and indeed the whole Minor Railway Section of the IRSE, comes down to the fact that those who have the custody of the UK’s minor railways are regarded as being just as professionally competent as their counterparts on the national network. In some cases, of course, the hydrae wear one head (or more) for their day job and another (or more) for their volunteer passion. It’s easier to talk that way.
With all the safety measures that are in place on Britain’s railways, including the need for the railway being fenced throughout its length, it is only at level crossings that trains interact with people. Pedestrians, cars, buses, trucks and babies in pushchairs share exactly the same space as 125mph trains.
It is not surprising, therefore, that making level crossings safer is a priority for Network Rail as well as for community leaders and Government. The problem is being tackled by the increasing use of proven technology that offers improved reliability and enhanced safety as standard.
Through its national level crossing framework contract, Infrasig, a joint venture (JV) company that unites Carillion and Bombardier, is renewing level crossings. By utilising Bombardier products and knowledge along with Carillion’s delivery teams, the JV is improving safety and reliability across the UK rail network.
Every installation is different
The Infrasig team has recently completed the design and build renewal of a number of level crossings on the Cumbrian Coast – Askam MCB (manually controlled barrier), Parksouth MCB, and Sandscale AOCL (Automatic open crossing, locally monitored) . It is currently in the construction / commissioning stage of St.Bees and Silecroft MCBs.
During the delivery of the crossings at Askam, Parksouth and Sandscale, Infrasig worked closely with Network Rail’s IP Central (North) delivery team in a collaborative working approach that successfully delivered the three level crossings within the extremely tight timescale of five months, as opposed to the industry average of nine.
As with all level crossing works, Infrasig had to meet challenges along the way. For example, at the Askam level crossing in Barrow-in-Furness, it transpired that the signal box and adjoining structures were Grade 2 listed and therefore required a different approach from the norm.
Items such as the URX (under road crossing), turning chambers and LCU (local control unit) had to be re-sited and bespoke construction methodologies were introduced including the removal, and replacement, of a large section of the Grade 2 listed wall to allow the installation of the URX cross-road ducting. This process was time-consuming and the Infrasig team had to work within some very precise and strict working guidelines with each brick being removed, recorded, washed down and then replaced back in its original position.
As well as the design and build contracts, Infrasig is also carrying out single option development contracts in Carmarthenshire (three MCB crossings), Stroud Valley (three MSL – miniature stop light – crossings) and Dovey Jcn to Pwellheli (three ABCLs and one TMOB – Trainman Operated Crossing with Barriers).
A kit of parts
For level crossing solutions, Infrasig draws upon Bombardier’s EBI Gate product family. This comprises a number of ‘tools’ that together make up a toolkit from which any particular application can be derived. These tools include EBI Light road traffic lights, EBI Gate 630 barrier machines, EBI Track 200 axle counters for wheel detection and EBI Gate 200 and 2000 level crossing controllers.
Bombardier has been working collaboratively with Network Rail for the past five years to improve crossing safety and reliability through the introduction of new technology. EBI Gate 200 is the first in the UK to achieve product approval for a safety critical PLC-designed level crossing system. It is now significantly more sophisticated than the early design concept in 2009, with continual data logging, reduced deployment restrictions and the ability to remove restrictive timers.
One of the enhancements to the EBI Gate 200 solution is a more robust auto-restore function that includes a full axle-counting feature. Therefore the system does not just detect the presence of a train but also fully counts the train in and out of the relevant block section and detects the direction the train is travelling.
The auto-restore functionality means that, during engineering works around the crossing area, there is no requirement to manually restore the system. The first train through the crossing area will restore the system to operational status, therefore improving availability to the crossing user.
These continual enhancements are part of a long-term product road map and Infrasig’s commitment to improve safety and reliability across the UK rail network. Bombardier is now working with Network Rail to integrate EBI Gate 200 within its Intelligent Infrastructure reporting system, while Carillion is improving the design, installation and testing methodology to achieve delivery savings.
Fully-integrated system
The next stage is to bring Bombardier EBI Gate 2000 to the UK. This is a full level-crossing system designed with the flexibility to be deployed as a total overlay solution, or as a renewal for an existing level crossing which can either be interfaced to existing signalling systems or fully integrated within an ERTMS signalling system.
When fully integrated, EBI Gate 2000 is completely controlled by object controller devices, therefore no conventional relays are required, improving reliability and reducing maintenance requirements. The system has a product design life of 25 years and is fully supported by Bombardier, therefore product lifecycle and obsolescence is proactively managed. The EBI Gate 2000 system is designed in accordance with CENELEC standards to SIL4 and is a complete self-contained factory tested system. In reality, this means removing the requirement for prolonged road closures, hence improving level crossing renewal efficiencies.
The full EBI Gate 2000 system consists of the EBI Gate 630 barrier machine, one thousand of which have already been proven in over one million operations. Deployed throughout Europe, it has the capability to drive 12-metre booms, well exceeding the current UK requirement of 9.1 metres. Its low current consumption, when compared to conventional approved barrier machines, will bring energy savings and deployment efficiencies with significantly reduced cable size requirements
This article was first published in Rail Engineer April Issue 126
Obstacle Detection (OD) crossings, which use radar to confirm a crossing is clear before clearing the protecting signals, are now fully approved with many installations completed and further ones planned. One of the first installations was at Four Lane Ends, due east of Burscough Bridge on the Wigan to Southport route. The commissioning of the OD crossing in May 2013 removed an unsafe crossing from the network.
Rail operators have explicit legal duties under the Health and Safety at Work Act 1974 to manage the risks arising from level crossings on their network. Any change or modification to the method of operation of a level crossing must only be done after a suitable and sufficient risk assessment has been undertaken to make sure that the risks have been reduced to as low as reasonably practical.
This has not always been the case and sometimes decisions have been taken with respect to the operation of a level crossing which, whilst appearing to be the right thing to do, actually imports additional risk. Such was the situation at Four Lane Ends.
Hand pumped
The crossing was originally protected with manually operated gates and a full time gate attendant based in the adjacent house. In the early 1970s, the crossing was converted to a User Worked Crossing equipped with Miniature Warning Lights (UWC – MWL) and the house sold. This type of crossing was normally provided on private roads with limited usage and it was unusual for one to be provided on a public highway.
Hydraulic ‘pump up’ barriers were provided. These required the road user to pump up the barriers by using a lever, provided the lights were green, and then lower them having passed over the crossing. The arrangements were authorised in a level crossing order, made under the British Transport Commission Act 1957, and issued by the Railway Inspectorate on behalf of the Secretary of State for Transport.
The MWL’s were operated automatically by approaching trains, displaying a red light when a train was detected approaching the crossing and a green light when it was permitted to cross the railway. The line speed is 70 mph. As its name suggests, four local roads converge on to Four Lane Ends Crossing, two from each side of the railway – plus there is a fifth driveway to access cottages.
In 1989, following several incidents with the barriers being left up by users, the level of protection was supplemented by the addition of a crossing keeper located in a caravan to operate the hydraulic pump. Unfortunately, as well as increasing operating costs, this change had the effect of increasing use by motor traffic as the crossing became more convenient to use.
The addition of crossing staff made the crossing’s status anomalous and by 1994 there was no provision in Railway Group or Company Standards for a UWC operated as a Manual Controlled Barrier (MCB). It did not have the benefit of safeguards that would have been provided for a compliant MCB, such as protecting signals or ‘approach locking’ via track circuits to prevent the barriers being mistakenly operated when a train was approaching. The crossing was designed for use by nominated users who would take responsibility for their own safe crossing and for their authorised visitors. The rail network operator now took over that responsibility, but without providing the appointed member of staff with the right tools for the job.
A new cabin
There were various attempts to renew the crossing with an Automatic Half Barrier (AHB) crossing. However such an installation was an expensive investment which got overtaken by more pressing schemes – the road layout would have required house demolition and extensive road modifications. The only enhancement that took place in the mid-1990s, was a more substantial crossing operator’s cabin with welfare and toilet facilities, to replace the temporary caravan.
Over time the crossing got busier due to nearby market garden businesses being established, the introduction of satnav promoting use as a short cut, a doubling of the train service from hourly to half hourly, and a nearby Sunday car-boot market. None of these changes were properly assessed for the increase in risk. Apart from the train service change, they occurred gradually over a period of time.
Because the barriers were operated whenever a vehicle approached, the crossing was required to be manned 24/7 (which even included Christmas Day when the network was shut). The crossing operators had to pump the handle to open the crossing in all weathers. They were walking many miles a day, receiving complaints from users, as well as making mistakes and operating the barrier when trains were approaching.
Electric operation
In 2006, the manually pumped barriers were provided with an electric pump. This was operated by a switch located in the crossing keeper’s cabin, with a supplementary one close to the north-side barrier machine. A mirror was provided so that the crossing keeper could see the indication of the miniature stop lights from inside the cabin. The new crossing equipment was authorised by a level crossing order issued by HM Railway Inspectorate and came into force on 8 January 2006. However the change in risk profile had not been adequately assessed.
The change improved the working environment for the operator, but making it easier to raise the barrier actually increased the safety risk. If the light changed to red whilst users were crossing, the operator had approximately 45 seconds to lower the barriers before the arrival of the train. Because they were not by the crossing, it was not possible to use hand signals to halt the traffic. There was no interlocking between the barrier controls and the signalling system, and there was still no approach locking provided. The crossing was used by over 200 vehicles per day, increasing to around three times this number on certain Sundays because of the car-boot market. Unsurprisingly, there were a number of reported incidents of trains traversing the crossing with the barriers raised.
In 2009 Network Rail sponsor Andy Scott became aware of Four Lane Ends when investigating the background to closure of nearby Shaws UWC. A footplate ride reinforced Andy’s concerns. During the journey, the train passed over the crossing with the barriers up and that was treated as a normal event by the local staff and public.
Obstacle detection
Finally, in 2010, a number of things coincided to provide a solution. Firstly, OD became an approved method of operating a crossing. Secondly, Network Rail improved its focus on level crossing safety and properly assessed the risk of each level crossing, and it put aside a dedicated budget within the control period to improve the safety functionality of signalling assets. Both the asset engineer and route director agreed a solution was required, and a key decision was to appoint Andy Scott as the commercial sponsor to properly develop the scheme, drive it forward, consult all stakeholders and obtain funding.
Andy consulted with colleagues, learnt of the long standing problems and set out to solve them. A survey was undertaken to establish usage of the crossing. About half was through traffic avoiding congestion in Burscough Bridge and half was local, with some using the crossing frequently during the day. A significant number of HGVs were serving a local farm to take turf to Liverpool.
When doing any work at a crossing, closure is always the first thing to consider. A consultation letter was sent to all nearby residents and local councillors, advising that closure or automation of the crossing was being investigated. Responses received were followed up by personal visits. It became apparent that those living south were unconcerned by closure or change but for those to the north the crossing was essential. In particular, HGVs could not access the farms by any other route due to either 3T weight restrictions or acute bends. A number of people thought that removal of the crossing keeper by automation would make it less safe, such was the lack of understanding of the situation.
A bridge would have had a significant environmental impact on the rich farmland, as would an alternative road route that was investigated. One solution was MCB with CCTV but this would have caused light pollution in a generally dark at night area. It may also have required additional manning in the controlling signal box, due to the already high level of crossing supervision.
The emerging OD technology offered a solution, providing greater levels of protection than CCTV but without lighting requirements. Both crossing solutions would need the area to have additional signalling, to include work on adjacent crossing controls, new line side power systems, track circuits and protecting signals for the crossing. At £3 million, the expected cost was less than the bridge and diversion option but still an expensive and long project to implement. Significantly, it brought resolution of the safety problem within Network Rail’s gift and not subject to lengthy legal timescales to acquire land that had an uncertain outcome.
Once retention of the crossing was agreed, it proved possible to make a business case to justify half of the expenditure on safety grounds and half from the operational cost savings. Risk assessment of the crossing suggested a 5% per annum risk of a fatality. Authority was granted for the full project at the outset, subject to mid-term review of costs. This meant that procurement of delivery could progress in parallel with the design work, saving around four months of process time.
Two near misses
Unfortunately, while the scheme was being developed, two near misses occurred which confirmed the need to improve the crossing.
On the 21 March 2011 the barriers were inadvertently raised for a car to cross. The crossing keeper had been using the toilet and when he returned to his desk he noticed a car waiting to cross and instantly raised the barriers with the light displaying red.
A short term measure was put in place consisting of separate raise and lower buttons which had to be pressed and held to cause the barriers to move. Lights on a panel repeated the indication of the miniature stop lights and an audible alarm was provided to sound for five seconds when the lights changed from green to red to alert the crossing keeper. This work was designed and implemented in-house by Network Rail and, as it was still not a compliant MCB, the necessary derogations to standards were obtained. All the operators were re-briefed and additional surveillance checks were implemented.
This was still not sufficient to provide a safe system and at approximately 18:20 on Friday 28 September 2012 train 2F87, the 17:03 passenger service from Manchester Airport to Southport narrowly avoided collision with a car that was crossing the railway. The crossing keeper made an error and raised the barriers when the lights were showing red in response to the car waiting at the crossing. He had been distracted by spilling a hot drink over a computer keyboard and did not check the indication of the lights before raising the barriers.
Closure
Following this incident, the situation could not continue. Lancashire County Council agreed to an emergency closure, followed by a temporary order through to the end of the works. This caused many problems to some of the residents and farmers, with longer journeys for work, schools and shopping. Damage was caused to the narrow roads that saw increased traffic. On 1 November 2012, a site meeting was held at which concerns were heard. There was an acceptance that the safety issue was significant and that Network Rail needed to press on – which was helped by the closure.
During the winter, residents had further cause to be upset as, independently of the level crossing project, it had been decided to fully renew one of the lines through the site using high output equipment. Lack of consultation over those works and inconsiderate practices by Network Rail’s contractors led to several complaints to which it was difficult to respond positively.
Behind the scenes, the project team pressed on with making sure that the necessary approvals would be in place for the novel technology. Following problems on Anglia route, a range of modifications were being proposed to the circuits and hardware. For example, provision of a shutter on the lidar camera to reduce the build-up of dirt – it only opens during the passage of trains.
Eventually, a trial certificate was obtained to allow construction and commissioning to happen, with modifications following later. Babcock was appointed as the main contractor with the design and implementation managed by its Crewe office.
Completion
Finally, on Monday 20 May 2013, the new OD crossing opened. Since then, there have been no reported safety incidents. OD problems have been with the supplementary lidar detector in the six foot causing a right side failure, due to the ingress of dirt and the detection of vegetation. Plans are in place, as with all OD Crossings, to provide a shutter to keep the radar clean which only opens when the device is required to sweep the crossing.
There have also been problems with the quality and availability of signalling relays that has affected reliability of the system, but these problems are not unique to Four Lane Ends or OD crossings, and the introduction of Programmable Logic Controller (PLC) technology will improve the reliability of other OD crossings and signalling control systems.
Shaws is an adjacent UWC-MWL crossing and, while located on a private road has had instances of miss-use. Now that Four Lane Ends has a compliant crossing, it may be possible to provide a short road diversion, close Shaws Crossing and remove another risk from the operational railway, all thanks to OD.
This article was first published in Rail Engineer March 2015 Issue 125
Developing new products is a challenge for any organisation, large or small. However, those that are well-established and have dedicated design and development facilities naturally find the process simpler.
One example is Chicago Pneumatic, founded in 1889 and a global brand leader providing tools engineered for demanding applications, designed and constructed to meet the rugged demands of Industry.
Many strict testing and quality inspections are conducted throughout the design, production and assembly stages to guarantee the long life performance of its tools.
Design and prototyping
Working in close collaboration with marketing to define targets to meet the needs of the end user, the design team develops a product concept associated with internal component details using CAD and simulation. This concept is then validated using prototypes.
Some prototypes are representative of the external appearance only, these are made with 3D printers. Others are representative of function and/or durability, in which case the critical parts are purchased from specialist suppliers or manufactured in-house.
Using its laboratories based in China, France and Japan, every new design is checked and validated. Depending on its complexity, each new design can be tested at every stage of development: prototype parts, off-tool parts or initial samples.
Quality production
Chicago Pneumatic understands that customer satisfaction is key to its continued success, indeed quality is a priority as products are constantly optimised so that the customer is offered the most suitable tool for the toughest of applications. All products are thoroughly tested and have to pass EC Certification according to ISO standards.
The company’s proven strategy of 100% partnering using only authorised distributors as a route to market has ensured that the end user only receives the latest best in class. All products are backed-up by technology training, air solution expertise, superior quality & ergonomics, and efficient customer support.
This allows Chicago Pneumatic to offer a large range of tools that provide enhanced performance and durability, readily available from stock and supported by a competitive pricing strategy.
Article was first published in Rail Engineer June 2015 Issue 128
Steel has many useful properties, which mean it is found in virtually everything around us – from the chair you may be sitting on to the vehicle you took to get to work today. Steel shapes our lives in more ways than you might initially think.
However steel has one property which isn’t so useful – it rusts. Steel is always trying to get back to its native state (Iron Oxide) and so, unless we do something to stop it, steel corrodes. How fast this happens depends on its environment and I’ll come back to this point as it is vital.
Protecting rail assets
If you look at pretty much any steel object in our rail industry, the steel used has some sort of corrosion protection. Whether this is galvanised overhead masts, paint protected vehicle chassis, line-side cabinets or even concrete sleepers, virtually all steel objects have corrosion protection built-in to stop the steel trying to return to its natural state. The most notable general exception to this rule is a fundamental part of our industry – the rail itself.
So why don’t we always protect the rails? – The key here is the expected life. In the majority of UK cases the rail will usually be replaced due to wear or rolling contact fatigue before it requires replacement due to corrosion, so protection in this case is unnecessary. However, as operating environments vary significantly, this is not always the case!
The rate of rail corrosion is highly dependent on the operating environment. There are several factors that accelerate corrosion vastly; the most common are water and salt, certainly something we are not short of in the UK.
Where these are present in areas such as coastal tracks, wet tunnels or level crossings, rail life may become determined by this accelerated corrosion. When this becomes the case, corrosion- protection of the rails becomes vital to optimise the life of the rail.
In severe environments, rail lives of just three months have been observed.
Failure modes
There are essentially two forms of corrosion-related rail failure. Rail gall is a general loss of rail section (usually affecting the foot). This can be general loss of section, but is usually more severe under rail clips/fastenings due to the localised environment here (water trap with abrasion from the clip/insulator).
Foot fatigue results from the combined effect of corrosion and fatigue. A corrosion pit forms on the foot of the rail and under traffic a fatigue crack can grow from this defect, ultimately causing complete rail failure. This is, in my opinion, the most problematic form of corrosion induced failure, due to the fact that you cannot measure it. Corrosion pits usually form on the rail foot (an area you can’t see or inspect), and in high load areas the pit only needs to be a few millimetres deep to start generating a fatigue crack.
The resulting crack is virtually undetectable via current in-track monitoring techniques, meaning control of this issue is problematic.
As the industry moves towards increasing rail life further by the use of more wear and rolling contact fatigue resistant rail steels, the proportion of rail replacement due to corrosion will likely increase unless we address this by adding protection where appropriate.
So how can we protect the rails against corrosion? – There are essentially two ways to prevent corrosion of steel.
Barrier coatings
This is one we are probably all familiar with; you create a barrier to stop the atmosphere/environment reaching the steel surface or, in other words, you apply a barrier coating to the rail. This is often a paint coating, but can be other things such as tar or rubber which is still used in some countries.
There are a number of drawbacks to this approach, though. The first is that any damage to the coating means that this area is unprotected and will corrode as fast, or indeed even faster, than if no coating was present. The second is that such coatings are usually unsuited to use where stray currents exist. Without going into too much detail, this means you can’t use them in third or fourth rail areas and also some overhead line locations, as any damage to the coating concentrates corrosion in the damaged area, resulting in extreme damage very quickly.
Sacrificial protection
Another way to protect steel is to apply a sacrificial coating to it. This corrodes in preference to the steel (so protecting it at the same time). This is why overhead line poles and many street lamps are galvanised. The zinc coating corrodes (slowly), in preference to the steel. Any small areas of damage remain protected by the coating either side of the damage (called the throw effect). The size of uncoated area protected depends on the operating environment. Under seawater, for example, the area protected is large and this is why ships use lumps of zinc on their hulls to stop corrosion. In the atmosphere the area protected is much smaller.
Historic rail coatings have typically relied on the provision of a simple barrier coating; however, our latest generation of corrosion protection coatings provide both barrier and sacrificial properties to ensure real-world robust rail protection.
Real rail protection
The environment provides some unique challenges to providing corrosion protection for rails:
» Impact resistance – Passing vehicles can hurl ballast at the rails, so an impact resistant coating is needed to prevent excessive damage;
» Damage tolerance – Almost inevitably something, somewhere will manage to breach the coating. Damage may be from ballast or damage from installation or maintenance operations such as damage from tamper tines;
» Stray current protection – Stray currents third/fourth rail operations as well as overhead, external or even some signalling current sources can cause rapid corrosion to most barrier coatings;
» Abrasion – Coatings are subject to abrasion and erosion particularly where clips/insulators or other track furniture contact the rail;
» Removal – For maintenance and installation purposes the coating needs to be removable (and indeed replaceable) in order to facilitate track welding.
To provide a corrosion- protection system that lasts requires optimisation of all these items to deliver longer rail life. Tata Steel has spent many years protecting rails from the elements and its coated rail solutions have provided some simply staggering extensions to rail life. The replacement rail installed into the level crossing pictured above has now exceeded 23 times the life of the original. This means improvements for everyone – passengers have a safer and less disrupted journey, maintainers and network owners have a lower risk network with less rail replacement to do, and the general public don’t have their road/rail crossing closed for rail replacement.
In the constant strive to improve product performance our latest generation coated rail product, ZinocoTM, provides maximum sacrificial protection with a step change improvement in durability for the highest level of corrosion- protection.
Written by Daniel Pyke, product marketing manager at Tata Steel.
Article first published in Rail Engineer October 2015 Issue 132
Railway track experiences all the climatic extremes the planet can throw at it. It is also subject to heavy loads, vibration, pollution and electromagnetic interference. This is not the ideal environment for an exposed electrical circuit that is a safety-critical element of the signalling system.
That said, track circuits are generally highly reliable but, when they fail, this is usually due to environmental conditions completing the circuit.
As the system fails safe, there is no safety risk but such failures have a high service impact. This is one of the reasons that axle counters are increasingly popular and are now the train detection system of choice for Network Rail.
This much was apparent from the recent 2015 Wheel Detection Forum in Vienna, which was a three-day event attended by over 200 delegates from 34 countries. This was the third such forum, a bi-annual event organised by the Austrian company, Frauscher Sensortechnik GmbH. However, this was not immediately apparent, as its focus was the benefits of axle counters, rather than its own products.
Keynote speakers
With the exception of Wabtec’s Dwayne Allan, the opening keynote speakers said little about axle counters. Dwayne’s presentation concerned axle counters in Australia and New Zealand where they were introduced in the 1980s. Their early use was on ‘long skinny railways’
as, unlike track circuits, there is no restriction on signal section length if axle counters are used. Other advantages of axle counters were the removal of insulated rail joints and the ability to alter signalling functionality during infrastructure upgrades.
Presentations on the project management challenges of installing railway infrastructure in the 57km Gotthard Base Tunnel and the expansion of Turkish railways were fascinating. As far as track circuits were concerned, the Forum learnt that the new Gotthard tunnel used Thales axle counters and that in Turkey there was a mix of detection systems, with track circuits presenting the greatest reliability issue.
Max Schubert of DB Mobility Networks Logistics explained how Fibre Optic Sensing (FOS) detects wheels and anything else along the infrastructure causing ground vibration. This may be quite tiny, for example a human footstep.
FOS measures changes in reflected light from micro deformations in a calibrated fibre that typically can provide a ‘microphone’ every 10 metres over a 40km length. With fibre cables commonplace along the infrastructure, FOS can make use of spare fibres without the cost of additional infrastructure.
The FOS technique is being evaluated on a 33km section of high-speed line in Germany. This has identified 27 potential applications, one of which is timely station announcements of trains approaching at over 160km/h. Initial results indicate that FOS can fulfil this requirement. Although it is not certain whether FOS can be developed to the safety integrity level required by signalling systems, this trial shows its potential for other applications in the near future. In Britain, FOS is now used to detect rocks falling onto the Oban line from the steep slopes of Ben Cruachan.
Axle counter system
For signalling, the axle counter system consists of the wheel sensor, axle counters and communication with the signalling interlocking. Modern wheel sensors are mounted on the inner face of the rail below flange height. They have two upward facing magnetic coils. Wheels are detected when the voltage of the alternating current in the coils is suppressed as a wheel flange passes over them.
This is not the simple piece of kit it might be thought to be. The coils need to be immune to electromagnetic interference, for which Frauscher has developed the V.Mix technology.
This combines three inductive processes (inductivity, field deflection and eddy current/ hysteresis) to increase the sensor’s resistance to electromagnetic interference, linear eddy current brakes and electromagnetic rail brakes. Coils also have to operate consistently between -40°C and 100°C, despite significant changes to the conductivity and permeability of the coils’ iron cores over this temperature range.
The axle counter is the electronics that interprets the wheel sensor output. To do this, the counter’s evaluation board (EB) converts analogue signals from the wheel sensor coils to a digital pulse. As well as counting the number of axles over the sensor, the EB also detects direction and speed by comparing signals from the two wheel sensor coils. It also has a logic circuit that counts axles in and out of each signal section to determine whether the section is occupied or clear.
The axle counter unit also incorporates a power supply with over-voltage protection. If not directly wired to the interlocking, it also has a communications board to transmit clear/occupied section data and receive requests for resets.
Resets may be required as axle counters, unlike track circuits, do not continuously detect trains. Instead, they use logic to determine whether a section is clear using data from individual wheel sensors. When normal operation is disturbed, for example by equipment failure or engineering work, the normal logic does not apply and a potentially disruptive system reset is required.
Automatic reset
The Frauscher FAdC axle counter system has a high availability as it is designed to largely eliminate such disruptive resets without compromising safety. As Phil Blacker of Atkins explained, this approach assumes that trains cannot fly or materialise out of nowhere.
The FAdC system offers two ways of doing this: counting head control or supervisor track sections. The basis of counting head control is that, as the axle counter system knows where trains are, it also knows when a train is approaching a wheel sensor. Hence, it can identify wheel sensor signals that are not trains, for example maintenance trollies.
Supervisor track sections are two adjacent track sections. If there is an abnormal operation of the middle wheel sensor, the sensors at each end of the supervisor section will still count the same number of axles into and out of the larger section. The supervisor track sections overlap so that each track section is part of two of them. If there is a track section fault, the sensor concerned can be automatically reset provided one of its supervisor track sections is clear.
UK standards do not yet allow for axle counter resets using counting head control and supervisor track sections. However, use of these techniques to improve axle counter availability is being actively progressed and has attracted worldwide interest.
Monsoons, lightning and pythons
The forum heard how monsoon floods, frequent lightning strikes and pythons climbing up overhead line masts affect tropical railways.
Whilst pythons are not a problem for the UK, floods are. Lightning strikes are also not unknown. Anthony Darama Rajan, signalling manager for Kuala Lumpur’s 59km airport link, advised that Malaysia has up to 250 thunderstorm days a year. He explained how axle counters had proved resilient to the flooding and made a significant contribution to the air link’s 99.83% on-time service performance, once wheel sensor earthing had been modified to prevent wheel sensor damage from frequent lighting strikes.
Flooding is an inevitable consequence of Mumbai’s monsoons, as illustrated by Sanjay Singh, S&T general manager of Mumbai Railway. His presentation showed packed trains running whilst water was at rail height as wheel sensors continued to function. With 7.6 million passengers a day on its 319 km suburban network, reliability of Mumbai’s signalling equipment is crucial. In 2012, Frauscher provided 1,900 counting heads and 1,400 track sections to upgrade this system.
Sanjay explained that, in addition to the sensor’s high environmental resilience, Mumbai’s railways achieve high signalling availability by using supervisor track sections, counting head control and redundancy from overlaying axle counters on track circuits.
This arrangement allows combined Counting Head Control and trolley suppression track circuits to avoid resets from use of maintenance trollies. Trolley suppression track circuits do not detect trolleys as they have insulated axles. Using Counting Head Control, the wheel sensor will ignore the two axles of trollies if the adjacent track sections or trolley suppression track circuits are clear. In case the track circuit gets occupied by the passing of another vehicle, the connected wheel sensor gets activated and following sections detect passing trains.
Ethernet communication
Various speakers mentioned the advantages of a decentralised architecture, made possible by modern transmission technologies. This presents security and reliability issues for which the Frauscher Safe Ethernet protocol has been developed as an option for system integrators who do not have their own protocol.
Providing the required software interface to exchange data between the axle counter and higher-level systems, this protocol also transmits data for diagnostics and centralised remote monitoring.
An example of such decentralised architecture is the modular signalling installed between Crewe and Shrewsbury in 2011 by Siemens, the first such system commissioned by Network Rail. This required 79 wheel sensors with the Frauscher FAdC axle counting system installed in 19 external cabinets. Communication between these cabinets and the Westrace interlocking is through an Ethernet connection using duplicated fibre optic cables.
Data transmission between axle counters and signalling interlocking by open Ethernet networks over a radio network also offers significant installation savings by eliminating cable routes. This does, however, present the challenge of providing a power supply for the wheel sensor. It seems this is not an issue for countries like Australia where the sun always shines on the sensor’s solar panels.
Level crossings
Speaking by Skype from India, Petchimuthu Gopalakrishnan advised how India’s 40,445 level crossings account for 44% of the country’s railway accidents. He referred to the advantages of axle counters for train detection.
In particular, he thought mass violations of level crossing rules by vehicle drivers would reduce if crossings did not have excessive warning times. In this respect, the easy adjustment of wheel sensors location was useful.
In Europe, level crossings account for 29% of all railway fatalities. José Fonseca of the Portuguese company EFACEC and Laurenz Trunner of the Austrian company EBE solutions are both concerned with the manufacture and installation of level crossing systems for which they offered the forum similar insights.
They both considered axle counters to be a more reliable and flexible solution than track circuits or treadles, an important consideration when railways have differing crossing detection requirements. They also noted that axle counters made it easier to optimise crossing warning times. Unlike track circuits, axle counters are not affected by rusty rails at crossings with few rail movements.
Ethernet-based communication reduced installation costs, allowed for remote monitoring of multiple crossings and supported integration with signalling and road traffic systems as required.
José Fonseca noted that EFACEC’s previous use of track circuits resulted in, typically, one defect per year per crossing. Since axle counters were introduced there had been virtually no failures.
Oiling the wheels
Presentations by America’s BNSF Railway, Progress Rail, Hegenscheidt and LORAM made it clear that large numbers of wheel sensors are used in non- signalling applications. For such use, Frauscher recently launched a stand-alone wheel sensor with an open analogue interface allowing it to be used with a wide variety of equipment.
Vennie Dyavanapali of LORAM estimated that, in North America, track lubrication systems use an estimated 25,000 wheel sensors of which around 90% are in yards with the remainder on the main line. Since 1900, flange lubricators have reduced the coefficient of friction at the gauge-face, typically to 0.05. Top-of-rail lubrication has been used in yards since 1995 and on the main line since 2005. This accommodates wheel speed differences on curves by applying a friction modifier to give a coefficient of friction of typically 0.3.
Wheel sensors ensure the correct amount of lubricant is applied. For top-of-rail lubrication, they also ensure lubricant is not applied until the locomotive has passed.
Axle counters monitor lubricant consumption and are used for billing. In yards, wheel sensors also control wagon speed, determine car location, detect stalled cars and activate wayside equipment such as scales and wheel cleaners.
Vennie noted that, for track maintenance, wheel sensors needed to be installed and calibrated in less than two minutes. They also needed a very low power draw, to be immune from AC interference, and to have wireless capabilities. Frauscher wheel sensors meet these requirements. In particular, with no requirement to drill the rail, sensors can be quickly installed as they are mounted using a rail claw.
Automated train monitoring
Hark Braren of BNSF provided another North American perspective with his presentation on the use of trackside equipment to prevent wagon derailments. This equipment uses various sensors, generally at common monitoring stations. Bearings are monitored by acoustic sensors and hot bearing monitors that measure surface temperature. A wheel impact detector measures flats and other wheel defects.
Vision Monitoring assesses bogie geometry for worn wheels and poor steering as well as broken springs and friction wedges. It also identifies missing fasteners, broken welds, damaged structural components, defective couplers, low air hoses and wheel tread defects. Accurate wheel detection is an essential part of these monitoring stations, both to trigger the monitoring equipment and specify the location of any train defects.
Progress Rail, Germany, has developed a vehicle monitoring checkpoint for use before tunnels. This detects dragging equipment, out of gauge loads and has hotbox detectors. Throughout Europe, around 1,200 FUES hot box detectors are in use, including 145 in the UK. These monitor external and internal bearings, wheels and brake temperatures. They require accurate wheel sensors to trigger the temperature sensors and provide data on speed and direction.
Wheel lathe company Hegenscheidt has developed its ARGUS II system to monitor wheels using various sensors to detect cracks and measure the diameter, roundness and wheel profile. This is done at up to 15km/h in a depot monitoring station that also identifies the train by, for example, transponders or optical character recognition. The results are stored on a database and used to assess wheel life and time to the next wheel turning. Accurate wheel sensors are an essential part of this system as the monitoring cameras and lasers need to be triggered at exactly the correct point.
Hegenscheidt’s Peter Neumann stated that this system is to be developed for main line use at speeds up to 100km/h. For this, the Frauscher wheel sensor triggers when the dip voltage of its two coils is equal. Initial results are that, at speeds between 40 and 60km/h, wheels of 513 and 755 mm diameter can be detected within ranges respectively of 5.2 and 3.2 mm. As this was not sufficiently accurate, further development work is being done.
Far and wide
The 2015 Wheel Detection Forum certainly offered wide-ranging presentations. Many had travelled far to attend it. No doubt, they found it worth their intercontinental journeys. This worldwide spread of delegates was a reflection of the installation of over 100,000 Frauscher wheel sensors in 70 countries, giving the company a market share of around 40%.
It was clear that axle counters offer significant benefits, so wheel sensors installations are likely to have significantly increased by the next Wheel Detection Forum, in 2017. It will be interesting to see what this next Forum has to offer.
We all live in a world where any form of disruption is a major issue which dramatically affects our wellbeing. The infrastructures we use on a daily basis, especially rail, roads and highways, constantly need maintaining as they are often used at full capacity. This problem also extends to utilities – water, gas and electricity distribution – power stations, marine environments and others. Much of this infrastructure, especially within cities and large towns, now can’t cope with the demands put upon it.
The net result is that these indispensible systems have begun to wear and fail at a higher rate and speed than may have been the case in the past. They now require a higher level of repair and maintenance to keep them operational, and this has to be carried out with less access time to keep traffic flowing and trains moving. As a result, there is an ever-increasing need for high-performing products to achieve the best level of repair in the shortest time.
A lot of infrastructure repairs require the use of cement. It’s easy to buy, simple to use, and relatively foolproof – in normal circumstances.
Re-engineering the product
Portland cement has been the standard for many years, but also has had some shortfalls. It shrinks excessively, can’t be accelerated without negative effects, is susceptible to attack by prevalent chemicals and reacts destructively with certain aggregates. None of this makes it ideal to use in today’s high- pressure maintenance environment.
CTS Rapid Set products provide cementitious solutions to this problem, with products that cure in a very short time and allow operations to continue with a minimum of disruption. There is also a specialist selection of additives available that give versatility of use to the three main products that are used to cover most repair and maintenance works.
Market leaders in USA, CTS Rapid Set products are fast becoming established across Europe, Asia and Australia and have recently been introduced to the UK. The three main products have recently been added to the London Underground Approved Products Register and are likely to be adopted for use within LUL civils maintenance works.
Rapid Set Cement is an advanced high-performance hydraulic cement that provides structural strength in one hour. It is manufactured with the same raw materials, equipment and processes used to make Portland cement yet has reduced shrinkage and superior resistance to chemical attack.
Precise selection and proportioning of the raw materials, many refinements throughout the manufacturing process and comprehensive quality control combine to give Rapid Set superior performance and a unique chemistry.
When Rapid Set cement is used in concrete, it provides superior performance in terms of rapid strength gains, reduced permeability and low shrinkage. Traditionally, when fresh concrete is placed using conventional Portland cement, the heavier particles settle and displace the water mix which then forms capillaries as it rises to the surface as bleed water. After the concrete has hardened, these capillaries become routes of entry for substances that attack the concrete and reinforcing steel.
When Rapid Set cement is used in concretes, repair mortars, or any other Rapid Set products, it produces ettringite crystals that rapidly consume water and create a three- dimensional lattice. This stops the settling and displacement process, eliminating the capillary formation which reduces permeability and resulting in a more durable concrete.
Comprehensive range
Rapid Set cement forms the basis for several easy-to-use products.
Cement All is a multipurpose product that can be used for general concrete repairs, doweling, anchoring, industrial grouting and form work. It can be used from a feather-edge up to 100mm thick, the surface does not need priming, and can be water cured. It has an initial set time of 15 minutes and can be trafficked in one hour.
Mortar Mix is a versatile product that can be used for general concrete repairs to floor slabs, vertical and overhead applications. It is a high performance blend of Rapid Set cement and quality sands. Mortar Mix is non-metallic and has no chlorides and, when mixed with water, it produces a workable high-build mortar that can be applied anywhere from 10mm to 150mm thick. It too sets in 15 minutes and can be trafficked in one hour.
Concrete Mix is a multi-purpose, fast setting product that can be used for repair and construction of floor slabs, machine bases, and general concrete repairs. It is a blend of Rapid Set cement, grades of sands and 8mm aggregate.
When mixed with water, Concrete Mix produces a workable, high-quality concrete material that is ideal where fast strength gain, high durability and low shrinkage are desired. It can be applied from 50mm – 600mm in depth, is durable in wet environments, sets in 15 minutes and is ready to traffic in one hour.
In addition, there is a range of specialty additives for retarding setting, increasing flow ability and including reinforcement fibres.
All of which can come in handy when repairing a railway at two in the morning when trains are due to start running in a couple of hours.
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