Muck – a very moving experience

26th February 2016

It must be a heart-in-the-mouth moment – that instant transition from mundanity to disbelief as you drive your train around a curve to find the line blocked by fallen trees. Where’s Jenny Agutter when you need her? So on goes the emergency brake, off comes the power; then all you can do is hope.

Those were the events that unfolded early on the morning of 7 January as an out-of-service DMU headed west through a cutting on the Newcastle-Carlisle line at Farnley Haugh near Corbridge. It struck the trees and came to a stand.

The driver’s report described water cascading down the cutting slope, turning to slurry at the bottom. When examining engineers attended, minor cracking was observed in the field above but, after 24 hours, these cracks had opened up considerably to expose a fractured main pumping raw sewage onto the hillside at a rate of 400 litres per minute. Coupled with this, similar volumes of water were pouring over the field towards the railway, the surface drainage having been overwhelmed. Things were not helped by the deliberate pushing-over of a dry-stone wall which had previously been acting as a dam and causing the nearby road to flood. With that, a Highways problem suddenly became Network Rail’s.

An initial conclusion was reached that the toppled trees were basically a function of a large washout flowing down the slope. As we all know, the North had suffered from record rainfall over the preceding weeks, with the December average exceeded by 300%.

Deep cut
To better understand the reality – which proved rather more complex – we need some historical context. Engineered by Francis Giles, the affected section of line was built by the Newcastle and Carlisle Railway, opening to goods and mineral trains between Blaydon and Hexham in November 1834 – a distance of 17 miles, most of which was single track.

Back then, there was no cutting at Farnley Haugh; instead the railway passed through a tunnel 170 yards in length. To handle an expected increase in traffic, this was enlarged after ten operational years to accommodate two tracks, the work being delivered with only one brief interruption to services when a failure of the original lining blocked the passageway with running sands.

The tunnel suffered from considerable water ingress and some distortion due to ground movement. Repair work was undertaken in 1871 at a cost of £1,000, and the arch was subsequently strengthened throughout with iron ribs and laggings. Concerns over gauge clearance and possible formation scour from the adjacent River Tyne led the Chief Civil Engineer of BR’s North Eastern Region to order the construction of a deviation. This resulted in the cutting being excavated between November 1959 and June 1962.

Photographs taken during those works show an area of rock pitching (riprap) mid-slope, used to stop weathering by emerging springs and coinciding exactly with the location of the landslip. Drawings were also extracted from the archives showing an unusually extensive drainage provision at this location. It was therefore reasonable to deduce that the engineers had been confronted by considerable groundwater issues.

Over the intervening 50-plus years, the cutting has not proven problematic except for a couple of minor washouts around 300 yards east of where the slip occurred. These were resolved by a refurbishment of the drainage in 2010.

Safety first
The operation to remediate January’s landslide was mobilised immediately, the works being undertaken by Construction Marine, Network Rail’s earthworks framework contractor for the London North Eastern and East Midlands route. AECOM was responsible for the design.

A compound was secured at the entrance to a field rented from the local farmer and traffic control measures introduced on the adjacent A695 to account for the number of plant movements. Despite the inconvenience caused, locals continued to support the on-site team with hotdogs and boxes of cookies. Around 30 of them accepted an invitation to visit the site over the first weekend to gain some understanding of what was going on. Relations have remained excellent.

Over the first four days, the project team progressed the urgent task of making the slope safe for workforce and machinery. With the inundation of water continuing, trees could still be heard cracking and falling to the ground. Northumbrian Water attended to turn off the sewer and divert it back 50 metres from the crest; meanwhile a field drain was intercepted and taken eastwards to a cascade at the top of the cutting where it discharged into a different drainage system. This allowed the slope to dry out…or at least that was the hope.

Eye in the sky
Initially, the intended methodology for disposing of the spoil involved moving it to the bottom of the cutting and taking it out by rail. However, large amounts of water were issuing from springs mid-slope – as had been the case during the cutting’s excavation – and liquefying the material. From a safety perspective, this instability rendered unsustainable the idea of bringing trains onto the site.

An unmanned aerial vehicle (or drone if you prefer), operated by Central Alliance, was brought in to perform a full photogrammetric survey of the landslide. This was repeated twice during the remediation. From thousands of geo-referenced digital images, a topographical 3D model was produced to an accuracy of a few millimetres. On the first pass, considerable interpretation was needed to account for the fallen trees – numbering around 100 – and reveal the ground profile. Without getting boots dirty, valuable information was derived on the extent of the slip, its shape and the volume of material involved – crucial in estimating how long the line might be closed.

Ground investigations, fulfilled by Geotechnical Engineering, found that the top part of the slope – to a depth of around 15 metres – consistently comprised glacial till: sands and gravels, with boulders of perhaps a metre across. Below this was a variable layer of clay, impermeable to water. At the surface, self-seeded silver birches covered the slope, together with some scotch pines. The former’s shallow root system acted to stabilise the ground to a depth of around 0.5 metres but, with the failure plane much lower, each one also acted as an approximately 20-tonne point load which tended to open the ground up as the wind acted on it. By saturating the sands and gravel with floodwater and sewage – increasing the weight of the ground above the clay layer by 40-50% – all the elements had come together for a significant slip. The back scar reached the line of the sewer where a trench must have been excavated at some point in the past 60 years. Could this have created a weakness which acted as a tipping point? We’ll never know.

What had become clear from observation, investigation and technical insight was that the landslide was not just a washout as originally thought. Something more significant was happening: a rotational failure in the hillside. This changed the complexion of the recovery operation.

The earth moves
The field above the slip hosts the buried remains of a Roman fort, discovered in the 1950s and comprising three camps. The nearest one to the crest – about 15 metres away – dates from just ten years after the Roman invasion. Archaeologists from Historic England were on-site for the first three weeks, supervising the removal of topsoil and recording any finds. Geophysics surveys were carried out to map the structures and ensure all works took place clear of them. Their presence did constrain the location of entry ramps into the cutting.

Tractor-mounted winches, sitting at the crest, were used to pull the fallen trees up the slope where they were fed into chippers. Some of what came out was used to form the surface for a 300-yard walking route from the compound to the site. Thereafter it was possible to get in heavy earth-moving machinery to start the regrading, taking weight off the top of the landslide – which otherwise would have continued to drive it – before removing material at the toe in order to clear the railway.

Throughout, it was regarded as an active landslide with established slip planes, so a constant balance had to be maintained as the slope was battered back from 1:1.6 to 1:2.5. At its peak, more than a dozen large items of plant were involved in the operation, from track dumpers to 40-tonne excavators. Around 35,000 tonnes of spoil was shifted and stockpiled in the field until a final resting place for it was agreed.

As a temporary measure, two deep counterfort drains were provided on the lower of two benches to deal with the water flows from mid-slope. A permanent, future-proof system will replace them as part of the full remediation works – now underway – which will also involve placing rock pitching on the lower slope to control shallow surface movement. Higher up, top soil and seed will see vegetation re-establish itself. There’ll also be inclinometers for monitoring purposes.

Whilst the p-way sustained no actual damage, the Down (Carlisle-bound) line did slew over towards the Up by around 100mm. The correct alignment was restored during tamping. Network Rail’s works delivery unit supplied a rail vac which, over two days, removed fouled ballast from a 70-yard section on each road, as well as a shallow cess drain. Around 600 tonnes of fresh ballast was put back. The vac proved significantly more efficient than the traditional approach, obviating the need to cut the track and lift it out, excavate, replace, weld and stress.

More to come?
Trains started running again through Farnley Haugh on Monday 8 February, barely a month after the line was blocked by trees and slurry. That’s no mean feat given the scale of the landslide and the difficulties it presented. The site will remain active well into the spring to deliver the final design, deal with the spoil and demobilise.

Thankfully, fire-fighting is something the railway is very good at. Just as well – there’s been lots of it to do since the storms ravaged Britain. If the climate change experts are to be believed, severe wet weather is set to become more commonplace during our winters. Whilst there is no emergency brake for that, we can at least see it coming. The challenge then is to make the infrastructure more resilient to its impact. That will have both financial and engineering implications, but it’s something Network Rail is committed to tackling into CP6 and beyond.

Resignalling in East Nottinghamshire

24th February 2016

A number of projects have taken place recently to abolish yet more lever frame signalboxes and mechanical signalling. Few of these remarkable survivors of nineteenth-century technology remain in main line service and it will be left to the heritage sector to ensure future generations know how signalling was achieved in the past.

One of the projects was in East Nottinghamshire, on the line from Nottingham to Grantham. Older readers will recall that this route was originally a Great Northern line (the Great Northern disappeared in 1922 – how old do you think our readers are? – Ed) and terminated at the now demolished Nottingham Victoria station. In 1967 a new connection at Netherfield enabled Grantham line trains to access Nottingham Midland station via the Lincoln route.

In 2013, Nottingham station was closed for a six week period whilst the entire layout of the station was remodelled with the signalling transferring from the 1969 Trent Power Box to the new Derby ROC.

This project extended the signalling boundary out to Lowdham fringe box on the Lincoln line and Bingham fringe box on the Grantham line, thus enabling modernisation of the route and associated level crossings in the city’s eastern suburbs. Eastwards of these locations, traditional mechanical signalling still existed including numerous level crossings. Modernisation was long overdue.

The East Notts scheme

Back in 2012, Network Rail developed a scheme based on the premise that the modular signalling solutions then coming on stream would enable a more cost effective and faster upgrade compared to conventional technology. Tenders were invited at GRIP stage 4 in the autumn of 2013, with a contract awarded in March 2014 to Signalling Solutions Ltd (SSL).

The firm had recently delivered its first modular signalling pilot project on the Ely – Norwich line. This enabled the modular approach to be developed and proven and, as a result, potential problems associated with this new and innovative approach had been identified and resolved.

New signalling was to be extended to Newark Castle on the Lincoln line and Allington Junction (close to Grantham). No permanent way alterations were envisaged other than the removal of some redundant crossovers and a new switch crossing at Newark Castle. No line speed improvements were instigated.

The signalling would be mainly two-aspect with discrete block sections but including some three-aspect signals where required. Allington Junction signalbox, commissioned in 2005 and equipped with an Entrance-Exit panel and relay interlocking, was built to accommodate the construction of a curve that eliminated a flat crossing on the ECML for trains from Grantham going towards Sleaford, Boston and Skegness.

At Newark, the Lincoln line crosses the ECML on the level with train movements being controlled from Doncaster Power Box. As such, the new signalling had to be interfaced with these controls. Derby ROC already had a Netherfield workstation under the Nottingham project with sufficient capacity to accommodate the two new lines.

Modular Signalling

The idea of modular signalling is to construct the necessary elements to a standardised design whilst also aiming to use pre-assembly and test in a factory environment to minimise the amount of installation and testing work needed on site. The East Notts project consists of:

An interlocking using the Alstom ‘Smartlock™’ electronic product already in use at many UK locations, the first being Horsham some 10 years ago. This equipment is positioned in the Derby ROC equipment room.
A ‘front end’ to link the signaller’s workstation and mouse to the interlocking, in this case using the well-proven Siemens (ex-Invensys) Westcad system. The two companies worked well together even though they are competitors on many occasions.
Local Trackside Functional Modules (TFM) installed in ‘Signalling Island’ Relocatable Equipment Buildings, known as SI-REBs, located adjacent to an existing junction or level crossing. These contain all the SSI (Solid State Interlocking) modules, transformers, rectifiers and relays needed for each location.
Local cabling out to signal points and level crossings pre-made in measured lengths with plug and socket connectors for ease of installation.
Train detection equipment using Thales AZLM type K axle counters.
A transmission link from Derby to the ‘Islands’ using the Network Rail Telecom-owned FTN network. These links are formed in rings such that any cable cut does not stop traffic being carried. ‘Points of Presence’ were established at all the SI-REB sites, from where the data streams are extracted. Alan Dick Communications (ADComms) at Scunthorpe was contracted to provide the interfaces between the FTN and the local cabling.
LED signals supplied by Unipart-Dorman for the red, yellow and green aspects but with a single aperture that can show the three colours.
In-bearer Clamp Locks by SPX for point operation (none required on the Grantham line).
Local power supplies from the local electricity company to supply the Islands and including a battery backed Uninterruptable Power Supply (UPS) giving a four-hour duration should the mains fail plus hard standing for a generator should the outage be prolonged.
Level crossing systems of various types, some existing and some new (see later paragraph).

Most of these piece parts can be assembled and connected off site as part of the integrity proving process.

Delivering the Grantham line

Only the Grantham line has been commissioned so far – over the weekend 27-30 November 2015. The work needed to construct and install the elements of equipment make an interesting account and demonstrate the involvement of many parties in a modern signalling scheme.

Key to any signalling project is the preparation of the control data that is loaded into the electronic interlocking – Smartlock in this instance. This task was carried out by SSL engineers from the York office and then tested at Derby.

The three REBs – at Bingham, Aslockton and Orston Lane – underwent several fit-out stages to accommodate power, lighting and signalling equipment. The REBs were made by Eldapoint of Liverpool, which provided power and lighting wiring and then transported them by lorry to Blackburn Standing of Nottingham for fitting with the power equipment and UPS. That done, they then travelled to MGB Signalling in Plymouth for fitting out with signalling equipment and racking procured jointly by SSL and MGB.

Next move for these REBs was to the SSL depot at Beeston, near Nottingham, where off-site testing could be carried out, known as a ‘hangar test’ facility. Here, by using a test Smartlock, verification testing, functional testing and principles testing can be carried out, connecting to either the signal/level crossing equipment powered up at the Beeston site or to simulations of the external kit.

Once completed, there is a high degree of confidence that the system will need only minimal on-site final testing. The equipment was then transported to the various sites and installed. Prior to this some considerable civils work had to be carried out including signal bases, REB foundations and level crossing alterations, this being contracted to Global Rail of Hatfield.

SSL used its own in-house staff for installation and for functional testing over the commissioning weekend. Bingham and Bottesford West signalboxes were closed with Allington Junction becoming a fringe to Derby ROC. The commissioning went smoothly and the line was handed back to traffic on the Monday morning as planned.

A number of modifications/improvements have been made to the SSL modular signalling system resulting from lessons learned on Ely – Norwich. These include facilitating easier fault finding and maintenance, equipment room reliability and overall system safety.

Level crossings

The Grantham line has a number of level crossings. Existing Automatic Half Barriers at Scarrington Lane and Normanton are largely unchanged (Normanton had a new signal within its strike-in point and thus needed adjustment to the control circuitry) but with their alarms and status indications now shown on the Netherfield workstation at Derby ROC.

At Bingham and Orston Lane, the manually controlled full barriers have been converted to Obstacle Detection semi-automatic operation (MCB-OD), whilst at Aslockton station, the previous AHB has been converted to an MCB-OD crossing. These use detection equipment to prove that nothing is trapped between the barriers, whence a sequence is initiated to lower them automatically and clear the protecting signals.

The detection process uses a combination of RADAR and LiDAR, the former mounted up to 915mm above rail level to scan the crossing as a general area, the latter (light detection) being two units, one at chest height, the other at near-ground level, to scan the roadway for any object that the RADAR might miss.
SSL was asked by Network Rail to manage the pilot introduction of OD technology on the Ely – Norwich project, but a key challenge was encountered with the low level LiDAR lens becoming obscured by dirt thrown up by trains and road traffic. As a result, all crossings using OD technology are risk assessed to establish if the lowest level detector is actually needed. Some light traffic crossings may be judged not to require it. Both LiDAR units are now equipped with a motorised shutter which automatically opens when the scanning process is taking place. This has solved the problem of dirt accumulation.

At Bingham, an additional safety feature has been introduced, namely Barrier Protection Management (BPM).

This comprises an inductive loop mounted in the roadway to detect if a vehicle is stopped where the barriers would come down. If activated, it stops the lowering sequence. The road here is much busier than the others and it is possible for traffic to queue across the railway. It is the first application of this feature by SSL but will be used elsewhere in similar circumstances.
Should any of the detection equipment pick up a problem, then the initiation sequence is stopped and the signaller investigates the situation, taking whatever action is needed.

Onwards to the Lincoln line

The Lincoln line will follow a similar pattern this coming autumn but with some added complications. Signalboxes at Lowdham, Fiskerton Junction, Staythorpe crossing, and Newark Castle, together with Gate Boxes at Fiskerton station and Rolleston, will be closed. The level crossings at these locations will be converted to MCB-OD operation except at Newark Castle. The barriers here are currently locally controlled from the adjacent signalbox and will be converted to remote CCTV monitoring under the control of Derby ROC.

AHBs at Gonalston and Thurgarton will stay the same but with alarms and indications sent to Derby. The AHB at Bleasby will be converted to MCB-OD operation.
With all these crossings to be altered and tested, it has been decided to commission the line in three stages, planned for September, October and November 2016, rather than having a changeover in a single weekend.

However, this does necessitate establishing temporary fringe boxes at Fiskerton Junction and Staythorpe for a short duration. The Newark flat crossing with the ECML will need an interface with Doncaster Power Box to be developed.

Lessons learned

Modular signalling can offer a much cheaper solution for secondary lines when compared to conventional signal technology. By using a state-of-the-art computer-based interlocking (CBI) like Smartlock, the system will be future proofed to accommodate ETCS. Cable lengths from the TFMs are calculated to be within limits to ensure effective immunisation for any future electrification.

This scheme has been the second modular signalling project for SSL and has enabled the company to consolidate the experience gained from the Ely to Norwich project. SSL believes it places the company in a strong position to deliver further modular-based schemes, realising re-signalling on secondary lines at a much lower cost than traditionally designed schemes.

Thanks to Andy Cokayne (project director) and James Suter (project engineer) for explaining the scheme in detail, and to Judy Viitanen for arranging the visit.

It all comes down to planning

23rd February 2016

Reflections - Stockley visit Francis Paonessa, Susan Cooklin and Toufic Machnouk 25122016 — Francis Paonessa, Susan Cooklin (route services director) and Toufil Machnouk (senior programme manager) at Stockley.

Over Christmas, Network Rail successfully invested more than £150 million to improve the railway across the country.

The Orange Army built new signalling, new bridges, new track and new facilities – all to give passengers better, more reliable journeys.

The investment will benefit millions of people. Commuters, families, friends; young or old, north or south, urban or rural; the impact the railway has on this country cannot be overstated. Whether you use the railway regularly or rarely (and more people than ever are using it regularly with passengers numbers having doubled to 4.5 million per day since 1997 and are set to double again in the next 25 years) the railway plays a vital role in our lives.

As well as passenger trains, rail freight carrying everything from cars, fuel for our power stations and the latest technology gadgets to your weekly grocery shop contributes £1.6 billion to the UK economy. That figure is predicted to rise to £2 billion by 2023. The demand from passengers and businesses to get more trains on the tracks brings with it immense challenges.

For some, Christmas might be the only time in a year they travel by train, but figures show (and the rest of the industry agrees) it is the quietest time of the year, and therefore the best time to work on it.

Network Rail has no rights to shut the railway and carry out our work when it feels like it, we need to consult and agree with the train and freight operators. However, train operators tell us that passenger numbers drop by up to 50 per cent during bank holidays such as Christmas and, while the reality is that there is no good time to do the essential work that is required, doing big projects and pieces of work over the Christmas and New Year period causes the least disruption and enables operators to offer decent alternative transport arrangements, especially as fewer people are travelling.

But we know from hard experience, of more than a year ago now, that getting it wrong and not ensuring that passengers are properly looked after has disastrous consequences.

The chaos, confusion and anger at Finsbury Park the Christmas before last remains etched on the minds of all of those who were involved.

he awful experience endured by the thousands of passengers who turned up expecting to travel on 27 December 2014 was unacceptable and one the entire rail industry never wants to see repeated.

What could have gone wrong, did go wrong, and the result was one of the worst experiences in my working career. We care deeply about those people who depend on the railway and, although the pictures on television screens, in newspapers and on social media sometimes tell a different story, I know from travelling the length and breadth of the country, meeting hundreds of members of the Orange Army, that our frontline staff feel the same way. They take a huge amount of pride in their jobs. They want to succeed and to return the railway in a better state than they found it.

The reality about major engineering work on the railway at Christmas is that, while 95 per cent of the network is unaffected, the five per cent takes years to plan. We started planning for Christmas 2015 back in 2012, firstly to identify what needed improving, then prioritising which areas needed more work than could be completed over a normal night or weekend shift.

Some people think that we save all our work up to do at bank holidays and wonder why we can’t do it at nights or weekends, but the reality is we’re out maintaining and improving the network every night of the week, not just bank holidays – last year alone LNE route did 16,000 jobs during evenings and weekends. Bank holidays allow us more time to do the biggest, most complicated pieces of work – such as demolishing and rebuilding bridges – while impacting the fewest people.

The Railway Upgrade Plan delivered this Christmas was the biggest yet, with over 8,000 worksites located in some 2,600 possessions on over 500 individual projects.

We had well over 20,000 employees and contractors’ staff working over the ten days.

The lessons of Christmas 2014 have now become part of our DNA and have proven their effectiveness with some £250 million of investment in hundreds of projects successfully completed in the four bank holiday work programmes since then – Easter, the two May bank holidays and August bank holiday.

Plan A was for all 500 Christmas projects to go exactly to plan. But things happen and then it becomes about contingency – plan B.
What if work falls behind? What if a machine fails or a train breaks or a driver phones in sick? What if the weather plays a part and we get blizzards or floods or gales that stop cranes working? How do problems at one site impact another? At what point can we stop the work or scale it back?
Our planning and operational teams across the country spent months analysing every scenario, what the consequences might be, and how we would deal with it. No stone was left unturned. Plans A and B were supported by an entire alphabet of alternatives and, like the railway itself, the decision-making process has been vastly upgraded.

The one thread that ran through every project, every review and every decision was simple; what might be the impact on passengers? In the past year we have changed how we deliver major upgrades and are working even more closely with train operators to make sure that every engineering decision is made with full sight of what that will mean for passengers and, importantly, how we are going to communicate with them. You may have seen our ‘Working For You’ advertising campaign featuring track section manager Barry Robinson from Leeds.

Despite the atrocious weather conditions, virtually all of our work was handed back safely and on time, with all our ‘top 20’ projects – the biggest and potentially most disruptive – handing back early. Over the period there were no major injuries and from the 2,600 possessions taken there were just 14 incidents of possessions overrunning and impacting operators. Most of these were very minor with the total number of delay minutes for the entire duration at under 400. As such, 99.02% of all possessions were handed back without impact to customers and we lost only 1% of our planned work owing to weather or decision to scale back to ensure right-time handback.

Thanks to all the preparation and planning, incorporating the lessons from Christmas 2014, the 2015 Christmas and New Year investment programme was a great success. A huge ‘well done’ and ‘thank you’ goes out to the tens of thousands of railway workers, planners, engineers, signallers, S&T staff, traincrew, crane operators, welders, station staff and numerous others who made this possible and should feel proud of all that has been achieved.

And a lot of this was done in some truly awful weather conditions where, once again, our people responded and put back together a railway that the weather had broken in hundreds of locations across the country.

This opinion piece was written by Francis Paonessa, managing director, infrastructure projects, Network Rail.

Video: Cheshire viaduct repairs

19th February 2016

New drainage systems are being installed on two Grade II listed viaducts as part of a £17 million investment on the West Coast Main Line. Dating from the 1840s, the structures’ original drainage had failed, causing track quality issues and numerous brickwork defects which are undergoing repair.

An 11-day blockade is needed to take the track off the viaduct and install pre-cast concrete ballast retention units which will collect water and discharge it into down pipes. An additional benefit of this solution is the relieving on lateral loadings into the parapets, the cause of longitudinal fracturing of the arch barrels.

Although clearly undesirable on such a strategically important route, the 11-day closure minimises the disruption caused by the works overall by driving efficiency improvements. Had they been done piecemeal, six months’ worth of weekend possessions would have been needed; around £500,000 of cost benefits are also generated.

As well as waterproofing the viaducts, two bridge reconstructions, remedial works to an overbridge and a considerable amount of routine maintenance has been progressed during the blockade.