At 06:30 on 24 May 2022 the Elizabeth line (nee Crossrail) finally opened. Authorised in 2008, construction started in 2009 and was originally due to be completed in 2018, it carried its first paying customers just five days after it was officially opened by HM Queen Elizabeth II and HRH Prince Edward, Duke of Wessex. It has cost just under £16 billion.
Joining the Paddington to Abbey Wood section to the existing Paddington-Heathrow, the Paddington to Reading and Liverpool St to Shenfield services were rebranded from TfL Rail to Elizabeth Line. The through services will be introduced over the coming year.
On a recent pre-opening visit to the line, your writer was amazed at the sheer scale of the stations; they make the stations on the Jubilee line extension, London Underground’s largest, seem small. At Liverpool St, it is also extremely deep requiring three escalators (one short, two long) to move from street to platform level. And, although all but one of the underground platforms is straight (Tottenham Court Road Eastbound is the exception), the line between stations is anything but, threading its way between many existing underground structures.
On opening day, apart from the first east- and westbound trains which were packed with enthusiasts and press, many ordinary travellers have been out and about on the line. Your writer caught an eastbound train from Tottenham Court Road to Abbey Wood and visited each station on a journey back to Paddington, with an extended stay at Woolwich where the great and good from the Crossrail project, TfL, and the mayor’s office were besieged by representatives of the general and specialist media.
The overwhelming impression is a cool, smooth, and quiet ride. A travelling companion said he could hear himself think. Compared with the screeching on the Bakerloo line and the heat and corrugation on the Victoria line, the Elizabeth line was serenity itself. In a 3.5 hour visit your writer observed a few first day teething troubles: one of the many escalators was out of action at Canary Wharf (not the Otis escalators used elsewhere), there was an empty train running around, and there was an evacuation at Paddington caused by dust in sensors, kicked up by the large crowds that arrived for the first services. That said, on the second day after opening, all trains ran and all were within five minutes of right time – representing an amazing public performance measure (PPM) of 100%.
The biggest impression of the morning was the number of people getting out their phones to photograph the enormous underground spaces, with the London Mayor, Sadiq Khan, reporting that some 260,000 journeys had been made on the first day. The photographs accompanying this piece give an impression but do not do justice to the sheer sense of scale. This is an important addition to London transport and, in a few years’ time, the delay and extra cost will have been forgotten.
With TfL’s Commissioner battling with the Government for a long-term funding settlement, one hopes that he can compare and contrast the Elizabeth line with the Bakerloo line. If he can take representatives to Paddington Elizabeth line, it is but a short walk under the main line concourse to the Bakerloo line, or, if something is not done soon, the Bakerloo heritage line.
Much has been written about Crossrail engineering in the general and specialist media, but one of the aspects that has had little publicity is the material the project team has made available as a learning legacy: https://learninglegacy.crossrail.co.uk offers a huge resource of documents explaining many of the challenges that the project teams have had to overcome.
The new Reston station saw its first train when the 05:29 TransPennine Express service from Edinburgh to Newcastle arrived at 06:16 on 23 May. This was almost 60 years since the original station closed in 1964.
Contractors BAM Nuttall started building the station in March 2021. It has two 270-metre-long, 4-metre-wide platforms on an embankment over an underpass and culvert. It required 251 precast slabs and 108 piles of which 60 were for the footbridge. This is a novel ribbon footbridge which was conceived by Arup, the station designer, and Knight Architects. It incorporates lift shafts on either side with the 17-metre-high north shaft serving three levels, the interchange (ground level), the north platform, and the bridge crossing.
Project engineer Jonathan Long advised that the work had to be done within the constraints of short rules of route possessions which required the footbridge to be erected in 12 lifts. There was one 54-hour disruptive for overhead line work which involved replacing five sets of single-track cantilever structures with portals and using this opportunity for overhead wires renewals. There was also a requirement to move one signal.
Reston is a small village of about 200 houses in the Scottish Borders, 47 miles from Edinburgh and 10 miles north of Berwick-upon-Tweed, close to several settlements including the coastal town of Eyemouth. The 70-space car park has been built in the expectation that the station will be a well-used railhead and so there is passive provision for a further 40 spaces. TransPennine Trains advised that they had advance bookings for 1,000 tickets from Reston.
The station is served by eight trains a day operated by TransPennine Express, except for a LNER service that provides a 07:27 service to London and an evening arrival from London at 21:41.
Scottish Transport Minister, Jenny Gilruth advised Rail Engineer that the £20 million investment provided by the Scottish Government for the new station would open up the area and that there are plans to improve bus links to maximise the benefit that the station will provide to the local community.
Various ceremonies marked the day, including Jenny Gilruth’s visit when she was met by a piper and 49 pupils from Reston Primary School who had been given train tickets by TransPennine Express for a day out in Edinburgh to mark the occasion.
Electric trains take power as it is generated and feed it directly into their traction motors without the need to convert energy or store it. Therefore, they will always be more efficient, more powerful, and cheaper to run and buy than self-powered traction. No amount of innovation can change this.
For this reason, except for the USA, railways throughout the world have electrified their core routes. Britain is another exception. On busy routes it has probably the world’s most intensive diesel passenger service and diesel provides 96% of the energy for its freight trains. For this reason, compared with other railways, the UK has a poor carbon record. Pre-Covid, UK rail’s CO2 emissions were amongst world’s worst with, respectively, 2.5 and 2 times the world average rail passenger and freight emissions.
For these reasons Network Rail’s Traction Network Decarbonisation Study (TDNS) recognised that electrification of at least 13,000 single track kilometres (stk) is needed to deliver a zero-carbon railway.
Yet despite the benefits of electrification, the Westminster Government is unwilling to invest in the electrification rolling programme recommended by TDNS. This is because it is not confident that electrification can be delivered at an affordable price. This is understandable given the cost overruns of the Great Western electrification programme which, despite a reduced scope, was delivered at three times the cost of the original estimate.
Thus, if there is to be a net-zero carbon railway the cost of electrification has to be reduced.
NEEP Speaking at a PWI conference in October, Network Rail’s Andrew Haines stressed that “we must not underestimate the harm done by the horrendous costs and schedule over-runs on the GW electrification. The ball is firmly back in our court to show that we can deliver cost-effectively, and that we can be trusted.” He also noted that “we must remember that we are publicly financed and must account for our expenditure. International benchmarks are there and used to measure our success, so we must push further.”
At the same conference, Prof Andrew McNaughton, previously Network Rail’s Chief Engineer and HS2’s Technical Director, advised that UK electrification was probably double what it costs elsewhere. He felt the job of engineers was to avoid unnecessary work and do unavoidable work efficiently using standardised elements and a factory approach. As an example of the former he mentioned the unnecessary proposal to demolish Steventon bridge as described in our feature on the PWI electrification seminar.
Against this background, the National Electrification Efficiency Panel (NEEP) was jointly convened last year between DfT and Network Rail. The ORR is also represented to identify issues that need regulator backing. NEEP is jointly chaired between Professor McNaughton and senior electrification engineer, Peter Dearman. Initially it informed the pricing of Midland Main Line electrification for its business case submission.
The first phase of the NEEP study considered technical opportunities and innovations to reduce the cost of electrification. It identified nine such action items:
Bridge parapets – secure widespread adoption of deriving parapet heights from risk assessment rather than a blanket application of 1.8 metres.
Voltage controlled clearances – roll out standards for the use of surge arrestors and insulated coatings as applied at Cardiff Intersection bridge to allow lower clearances to be derived from a suitable risk assessment.
Track vertical allowances – derive economically affordable track lift allowance to protect locations with tight vertical electrical clearance.
Trial holing alternatives – avoiding hand digging trial holes at every OLE foundation with, for example, the use of ground penetrating radar.
Insulated pantograph horns – adopt this type of pantograph which are used throughout Europe and elsewhere.
Wire gradients – update design principles to avoid infrastructure interventions in close proximity to level crossings and bridges.
OLE structure spacing – changes design rules to reduce the number of structures per mile by optimising spacing.
Rationalised traction distribution principles – reduce the number and scale of electrical substations with designs that use the best modern practice in electrical power switchgear and control design.
OLE structure design range – limiting the available range of structure types in the UKMS design range to reduce supply chain complexity and improving the visual appearance of OLE.
These initiatives are all being progressed and some have resulted in E&P Technical Advice Notes which are early notifications of a standards change. NEEP continues to monitor progress with all these initiatives and to push for their mandatory adoption. Dearman feels that there is a need to educate the devolved Network Rail organisations on the approaches to risk management and whole life cost which need to be embraced if these initiatives are to be successful.
The next stage of the NEEP study is consideration of non-engineering issues including procurement models, risk ownership, methods of project delivery, use of plant, and overhead costs. A particular issue is that, in the UK, instead of a continuous production model, electrification is delivered as a series of distinct projects which have set-up and close-down costs. In addition, end date targets increase costs as extra resources are procured to meet an arbitrary target date.
Dearman advises that, of all the cost issues, the early NEEP phase 2 work has identified that overheads are a particular issue in the UK. This reinforces his experience working outside the UK where, as McNaughton observed, electrification costs are probably half of those in the UK. Many of the delegates at the PWI electrification seminar also expressed similar concerns. Indeed, one speaker at this seminar considered that UK electrification required more paperwork per stk than any other country in the world. It seemed clear that no-one disagreed with him.
Dearman felt that this was due to excessive man marking with unnecessarily large safety, assurance, commercial, and planning teams. His research had found that overhead costs in Europe were typically 50% of the cost of physical works (materials, labour, and plant). In contrast, in the UK overhead costs of 150% are more normal.
If these figures are correct, it means that, even if the technical opportunities that NEEP has identified can reduce the cost of physical works by 50%, this will only reduce total electrification costs by 20%. This shows the importance of this aspect of NEEP’s work although it is likely to produce some tough messages for the industry. However, the tougher message is that unless electrification costs are significantly reduced further electrification is unlikely to be authorised.
At the October PWI conference, Andrew Haines referred to the great work being done in Scotland where electrification costs are as low as £2 million per single track kilometre and further reductions are credibly expected. Much of this is due to there being a continuous programme in Scotland where the supply chain is trusted to deliver. Yet south of the border the industry has still to gain such trust, which is needed if the Westminster Government is to commit to a rolling programme of electrification that itself would reduce costs.
This explains why NEEP is an essential initiative. Rail Engineer looks forward to reporting further on its findings which could be the key to achieving a net zero carbon railway.
Delivering the business case’ was the particularly apt title of the PWI’s electrification seminar in Glasgow in April. The 140 delegates who were present know that electrification is required but convincing the Westminster Government requires electrification to be demonstrably affordable. Although various speakers described actual and potential cost reduction measures, the cost of electrification remains high at a reported £2 million per single track kilometre (stk) in Scotland and £3 million per stk in England.
This compares with £500,000 stk for German and Swiss electrification as shown in the Railway Industry Association’s Electrification Cost Challenge report. Some of these high costs are outside the control of delivery teams such as high overheads, project process issues, and the lack of a rolling electrification programme. The frustration of those who had built up experienced electrification delivery teams only to disband them at the end of each project was particularly notable.
Bill Reeve, Transport Scotland’s director of rail and Alan Ross, director of engineer and asset management for Network Rail Scotland, explained why Scotland has a rolling programme and how it is being delivered.
Scotland’s rail decarbonisation plan
The Scottish Government considers rail electrification to be an essential part of its national transport strategy. Since 2010, it has funded 325 stk of electrification. Currently electric trains carry 76% of rail passenger traffic and haul 45% of rail freight in Scotland. Its Scottish Rail Services Decarbonisation Action Plan, launched in July 2020, will decarbonise rail passenger services by 2035.
Bill Reeve explained this plan is an instruction to the industry to electrify all Scottish main routes. He noted that battery and hydrogen trains will have a role but not for the core railway or for freight, as electric traction is essential to provide the longer, faster trains needed to meet rail freight growth targets for which gauge clearance is to the electrification programme.
Regardless of the decarbonisation imperative, Reeve explained that electrification is needed to make rail competitive as electric trains are cheaper to operate, more reliable, offer faster trains and additional services. They are also cheaper to buy than diesel trains which will need to be replaced in the not-too-distant future. For all these reasons Scotland can’t afford not to electrify.
Reeve also explained that a competitive railway is needed to attract the modal shift from cars if Scotland is to meet its decarbonisation targets which include a 20% reduction in car kilometres by 2030. Reeve noted that simply changing cars from petrol to battery powered “won’t cut it”.
Hence, Scotland is committed to a rolling electrification programme derived from a whole-system approach that considers the optimum infrastructure and rolling stock solutions to deliver the required timetable. This also gives the supply chain confidence to develop its workforce and capabilities. Reeve concluded by stressing that all this depends on cost effective electrification delivery.
Alan Ross then explained how the decarbonisation programme is being delivered. He also stressed the need for a rolling programme to drive costs down but accepted that this requires trust and commitment. In this way, rather than individual projects, electrification is delivered as a programme which offers opportunities for optimising logistics, packaging feeder station delivery and procurement savings with early purchase of raw materials. He emphasised the need for a “sweet spot” to optimise delivery volumes which, for Scotland, is the annual delivery of around 90 stk of electrification and 30 structures clearance interventions.
Although Scottish electrification had generally been delivered within its cost envelope at around £2 million per stk, costs still need to be further reduced. This requires transparency to ensure all cost drivers are understood, the need for a culture that embraces continuous improvements and a production focus. Ross recognised that Network Rail had to respond to the supply chain’s concerns, particularly in respect of access strategies.
He also described how Scotland’s whole system approach helped to determine the best overall solution. For example, the need to withdraw diesel units in the next few years requires an interim strategy of discontinuous electrification with EMUs fitted with batteries that can be removed in future. Such an approach provides incremental benefits prior to full electrification.
Scotland’s electrification has challenges, of which its most iconic structure is one. Ross considered that Forth Bridge electrification is “challenging but doable.” There are also significant gauge clearance issues elsewhere, particularly on the Highland Main Line. He also noted that power supply in remote areas is also a challenge for both Network Rail and the National Grid.
Delivering more electrification than ever before over a 13-year period with ongoing cost savings is a significant challenge. With everyone playing their part, Ross feels this is achievable.
Stirling Alloa Dunblane (SDA)
Warren Bain, PBH Rail’s technical director, explained how the recent SDA Scottish electrification programme started in January 2016 with its first OLE Form A. It had to be completed by December 2018 so that new Hitachi class 385 EMUs could replace the class 170 DMUs that had to be released south of the border. SDA provided 110 stk of new electrification which included 2,200 new structures with an expanded feeder station and two new Track Section Cabins.
For SDA, PBH rail developed a single section pile up to eight metres in length to avoid splicing the high percentage of piles that were longer than the standard 5.5-metre length. These piles were developed in consultation with the fabricators after confirmation that piling rigs and trailers could lift and transport these piles. A particular challenge of this project was the 600-metre Kippenness tunnel, that had a low uneven roof in which OLE structures could not be installed at the low points.
Production based electrification
Rob Sherrin of Leeps Consulting has no doubt that electrification needs a production rather than a project philosophy. He quoted cost savings from repetitive programmes such as windfarms that are expected to generate electricity more cheaply than gas-fired power stations in 2023, and Network Rail’s Southern power supply upgrade which was around £800 against its £1 billion budget.
The need for such a production approach was highlighted by a questioner who asked why the GRIP language of projects is used for electrification which should be a continuous process. There was no satisfactory answer to this powerful question.
He advised that English electrification was currently costing about £3 million per stk and that this must be reduced with a relentless focus on costs and the efficiency of repetitive tasks. He considered that the overheads and prelims must be reduced as these were often many times the cost of the actual work. Also, innovation needs to focus on cost and eliminate complexity, the access regime needs to allow efficient production and multiple packages of work will provide competition.
Sherrin also felt that the authorisation regime needed to be challenged as the Common Safety Method needed to be applied on the basis that there are no new fundamental risks from railway electrification schemes.
Amey’s engineering manager, Anne Watters, reinforced many of Sherrin’s points. She explained how a 50% increase in possession time (from four to six hours) could double working time (from two to four hours) and therefore cancellation of the first and last trains of the day needed to be considered.
She also considered the practicalities of using different types of machinery. High Output trains had their advantages but needed to be able to store sufficient material for an eight-hour shift. Road Rail Vehicles (RRVs) are useful in complex areas but may not be efficient if their access points are miles apart.
Watters also stressed the importance of developing the workforce and that this related to the access regime as excessive reliance on Saturday night working increased the need for “weekend warriors.” A continuous programme also facilitates apprentice schemes, avoids efficient teams being disbanded and is needed if there are to be sufficient OLE construction trainers.
She considered that other benefits of a rolling programme were a long-term look ahead of route clearance work, enabling it to be done first, and consistency of standards. She noted that she had spent hours discussing standards for station foundation designs.
The respective M&EE professional heads of Swietelsky and Babcock, Calumn Oates and Nick Wilkinson, explained how Swietelsky Babcock Rail had developed specialist electrification plant. Its self-propelled Kirow 250 Rail Crane can be fitted with a side mounted tube driving system that can drive up to five piles per hour at a maximum 16-metre reach. They explained how their cranes can also be used to install masts and gantries. A continuous programme is needed to make the best use of this impressive, though expensive plant.
Preparing for electrification
Alan Kennedy, lead OLE engineer for SPL Powerlines, considered pre-work measures to maximise efficient delivery. He considered digital twin to be a real step change as they reduced the requirement for on-site surveys as well as improving design and constructability reviews.
Another promising development is ground penetrating radar (GPR) to reduce the need for trial holes. This enables around 25 locations to be surveyed in a shift which would otherwise dig one or two trial holes, though GPR does not completely remove the need for trial holes. Instead, it allows them to be targeted as required. Kennedy explained how GPR is being trialled on the Haymarket to Dalmeny (H2D) scheme that should have its first piles driven at the end of June.
He also described trials undertaken at a local quarry to determine the best method of rock piling and its effect on possessions. Methods tested included down-the-hole (DTH) hammers, micro-piling, and coring or auguring.
Reducing ‘boots on ballast’ and maximising time on track are key principles of efficient electrification. This can be achieved by off-track OLE construction and pre-registered cantilevers attached at site. Kennedy advised that this reduces site visits from three to one prior to wiring. However, this approach requires mature design and space for fabrication. It also needs a gap between foundation and OLE work to make it efficient.
He also explained how maximising span length at Almond viaduct on the H2D scheme might save £250,000 as the viaduct was not suitable for attachments. Although still to be confirmed, it was expected that the required 88-metre span would be feasible. Certainly, this approach has wider benefits in similar locations.
Kennedy’s presentation reinforced many of the points made in earlier presentations including the need to optimise access strategy, keep things simple, the need for a more appropriate assurance regime, and the development of the workforce.
Another issue that needs to be considered early in any electrification scheme is its heritage implications. Michael Ponting, overhead line solutions lead for Jacobs in York explained what this entails. There are potentially many stakeholders involved with any affected stations, overbridges, and heritage assets close to the railway. Early engagement with such stakeholders is essential.
Although electrification normally requires a standardised approach to maximise efficiency, heritage impact mitigation may require a bespoke solution to be agreed with stakeholders, at an early stage of design. Ponting also emphasised the importance of challenging standards to, for example, minimise heritage impact.
Kennedy referred to the useful guidance in Network Rail Standards NR/GN/CIV/100/02 “Station Design Guidance” and NR/GN/CIV/100/05 “Heritage: Care and Development”. These show that there are over 200 listed stations in the UK, all of which require conservation management plans to be prepared in consultation with the Railway Heritage Trust.
Garry Keenor, professional head for electrification at Atkins, gave a presentation focused on design cost reduction by digital design and challenging standards. He said that with typically 3,500 structures for 100 stk of electrification, design was a volume game that needed to be automated as far as possible using the latest digital design tools. He noted the importance of defining minimum viable product and emphasised that design development is the time to reduce costs, though this needs planning further ahead.
He explained that some standards may be out of date and that the historic reasons for them may not be clear. Hence there was a requirement for intelligent rule breaking to challenge standards using an evidenced based, first principles approach. He gave two examples where there had been a successful challenge: allowable uplift and wire gradients.
Until recently, the design uplift for contact wire bridge arms was 70mm. Keenor explained how novel measurement techniques that required no track access of OLE mounted equipment had demonstrated this could be reduced to 45mm.
A study of wire gradient was the result of it not being possible to demolish Steventon bridge during the GW electrification works. As this bridge was 400 metres from a level crossing, bi-mode trains had to operate on diesel power underneath it. This was because the then standards required a 60mph speed restriction of electric trains on the resultant 1 in 202 gradient and a maximum 1 in 625 gradient to operate at 125mph. After modelling and test train running undertaken by Atkins, it was demonstrated that electric trains could run at 110mph on a 1 in 175 wire gradient.
Keenor said there needed to be a cultural change to encourage intelligent challenge and interpretation of standards. He encouraged Network Rail and its contractors to follow the E&P Technical Advice Note Ref 12-21-001-V1 “Bridge parapets electrical risk assessments” which introduced a risk assessment methodology to determine the required parapet works. He emphasised the need for simplicity, both of design and process, and made the tongue in cheek observation that Britain requires more paperwork per electrification stk than any other country in the world.
Atkin’s Technical Director, Paul Hooper, considered what UK electrification might look like in 2050. Although Scotland is implementing its rail decarbonisation plan, the Westminster Government has yet to commit to an overall plan of rail decarbonisation. It has also not responded to Network Rail’s Traction Decarbonisation Network Strategy (TDNS) which recommends 11,700 stk of electrification with battery and hydrogen trains respectively operating on 400 and 900 stk of track with currently no clear technical choice for 2,300 stk.
He noted that there were various proposals for discontinuous electrification though this was not suitable for freight. This is to be a permanent solution for Transport for Wales as the South Wales Valley lines are electrified. Hooper considered that this will require an ultra-reliable system for pantograph raising and lowering. It will also need battery size to be optimised which may result in bespoke trains.
In Scotland, the plan is for interim discontinuous electrification which needs to be planned around nine new feeder stations and take account of the need to provide power for both traction and battery charging. He noted that a rolling programme needs a five-year look ahead, especially in respect of power supplies.
New technology such as intelligent infrastructure, digital twins, and static frequency converters can reduce costs. However, Hooper emphasised that the electrification programmes should not await future innovations but be planned on what we know now.
Hearts and minds
Mott MacDonald’s head of rail systems, David Wilcox also considered the traction mix recommended by TDNS and explained this in terms of how far a train can travel per kilowatt hour. It might be obvious that electrification is the optimum traction and decarbonisation solution, but it is essential to win the hearts and minds of politicians.
He considered that a whole system approach needed to be taken to maximise performance and minimise energy consumption. To illustrate this, he considered a bridge on a 1 in 200 gradient on the Borders Railway with a 60mph speed restriction on a 1 in 80 gradient. He wondered how long it would take to recoup the cost of eliminating this restriction from the resultant fuel and performance savings.
He echoed the points made by previous speakers about challenging standards, data driven design and digital twins and wondered how long it might be before drawings were not needed.
Looking to the future
Decarbonising the railway with a rolling electrification programme that provides cheaper, faster trains to attract traffic from less carbon-friendly transport is a vision for the future that is being delivered in Scotland. Hence Glasgow was a good venue for the PWI’s electrification seminar which highlighted examples of good practice in Scotland and elsewhere.
With many speakers stressing the importance of developing the workforce, the presentation by Megan Schofield on attracting young engineers to the industry was particularly well-received. Meghan started her railway career with Arup just over two years ago as a graduate OLE engineer. In her first job she worked on platform extensions at London’s Liverpool Street station. This was a small job involving all disciplines which she felt provided a good learning experience. She is now working on the Transpennine upgrade.
Schofield advised that, at university, her fellow students did not consider rail as a career and instead looked to the automotive, aerospace, and oil and gas sectors. Hence, she posed the question of what the industry can do to attract more engineers. She also felt that it was important to get more young people into engineering at an early stage.
She also felt that mentoring was important and advised managers to inspire those less experienced than themselves by spending quality time with them. She recognised the importance of networking and felt it important to have strong female leaders in engineering teams.
In the following Q&A session it was noted that Megan had clearly shown the importance of learning by doing and that mentorship was not a one-way process. One senior engineer acknowledged how much he had learnt from younger engineers.
In summing up the conference, its chair, Peter Dearman, considered that it was uplifting to hear that in Scotland, Bill Reeve, representing Government, and Alan Ross of Network Rail were talking the same language. Yet he cautioned that the UK has the highest infrastructure cost base in Europe and that, even if material cost was zero, UK electrification would still be more expensive than in Europe with much of this due to high overheads.
Regardless of the Scottish example, much still needs to be done to convince the Westminster Government of benefits of electrification and that the industry can deliver at an affordable cost.
Folkestone was once an important harbour and shipping port. Nowadays, it is home to Dollands Moor freight yard which was built to serve the Channel Tunnel. The Dollands Moor DC Substation sits at the western end of this freight yard and was originally constructed as part of the Channel Tunnel Reinforcement Scheme in the mid-1990s.
Network Rail decided to remove Dollands Moor DC Substation from service at the end of 2019 due to water ingress, reliability of DC protection relays, unavailability of spare parts and lessons learnt from the Godinton Substation incident where a Network Rail colleague was seriously injured. Since then, the substation was watching trains passing by without being able to contribute to the network. However, its fate was changed when Network Rail initiated the works to bring the substation back to operational service to improve the performance of the DC network.
Network Rail deemed Dollands Moor as a high priority and required the project to be completed as soon as possible. BAM Nuttall, as the principal framework contractor of Network Rail, immediately started the planning. The company was aware of the level of complexity, the tight deadlines and the significance of the project; hence it had to ensure that the designer has high expertise and resource to cope with those challenges. Rail Power Solutions, being one of BAM Nuttall’s preferred Electrification & Plant (E&P) designers, was approached to develop this highly challenging design.
Retrofit to increase safety
According to the Godinton report, concerns were identified with the existing DC switchgear, combined with the formation of condensation which contributed to the incident. Dollands Moor DC switchgear was chosen as a trial site for undertaking design and implementation works to improve its reliability, electrical clearances, and maintainability. In addition, there was a requirement to extend the asset life for a minimum of 15 years.
The DC switchgear, which was installed in the 1990s, has a protection system that does not comply with the current Network Rail standards. Network Rail’s preference was to replace the complete protection system including the DCTR-1B protection relay, Hall effect transducer for current measurement, Hall effect check transducer, Hall effect sensor, Hall effect power supply unit/amplifier, and DC voltage transducer. This means redesigning the majority of the non-removable parts of the DC switchgear.
An alternative solution was the complete renewal of the DC module which would come at a significant cost. However, given the vast number of this type of DC circuit breaker on the network, a retrofit option applicable to the majority of the breakers was considered a more cost-effective approach.
Following multiple options proposed by Rail Power Solutions during the GRIP 3 stage (option selection), Network Rail agreed to a single option that provides a practical retrofitting solution without compromising on safety. The design included works in track cable termination, relay and transducer chambers.
“Dimensions were obtained on-site to develop the design. However, the partial use of existing copper work with a different configuration, installation of an additional shunt, and the requirement for additional angled copper work introduced significant uncertainties. It is like playing a 3D puzzle, but you have to create the puzzle pieces. Although we were confident of the design, timescale and cost implications were the last thing we wanted during the construction phase. Assembling the real scale 3D parts on-site helped us to identify any details we missed and to confirm the accuracy of the dimensions.” William Fonseca, Director of Rail Power Solutions.
Design challenges and innovations
The configuration of the copper work of the DC Switchgear at Dollands Moor created concerns about the space available for the installation of new equipment within the cable chamber. The design became more challenging due to the absence of record drawings showing the exact dimensions of the existing copper arrangement in the cable chamber. Rail Power Solutions had to attend the site multiple times to confirm the suitability of the proposed shunt and copper arrangement.
Following discussions with BAM Nuttall, the parties suggested introducing innovative technology into the design process using 3D copies of the shunt and proposed copper work to check effectively the suitability of the new arrangement before finalising the design. Given the very short lead times for 3D prints, it provides more flexibility and is time-saving and cost-effective compared to supplying the actual copper parts and shunt during the design stage.
Rail Power Solutions produced the 3D model of the parts using the dimensions obtained on-site and got the parts 3D printed. On the next visit to Dollands Moor, the engineers were more confident in the design since the 3D model showed that the proposed copper work and shunt would precisely fit the cable chamber.
“A collaborative team effort from all at RPS, BAM Nuttall, and Network Rail. Despite the short time frame, a challenging project was delivered.” BAM Nuttall contracts manager, Duncan Hall.
Rail Power Solutions’ primary design objective was to make minimal modifications to the existing copper work to reduce the retrofit’s risk and cost; while increasing the repeatability of this design to similar types of DC switchgear. The safety of the operators and maintainers was the main driver of the design. Additional measures were implemented in the design, to prevent contact of maintenance personnel with 750V circuit, this included: a new type of fuse holder that is operated with the use of a hook stick to allow operators to isolate parts without entering the breaker cell; additional shrouding; and warning labels.
Another aspect of the design was the anti-condensation heating for the DC switchgear. The substation was originally built at a time when the internal environment characteristics of steel buildings were not as well understood as they are today. The steel construction can be susceptible to the formation of condensation, and the condensation can contribute to the electrical flashover. Although the building had been provided with de-humidifiers, additional heating in each breaker was required.
Space constraints inside the circuit breaker were once again an obstacle. Thus, Rail Power Solutions proposed compact dynamic heating elements with a significantly small footprint. In addition, the electrical clearances were improved to eliminate the occurrence of any electrical flashovers.
Following the installation and entering the substation into service, all parties are happy with the result. Although the Godinton incident raised significantly the bar for safety, the design as a prototype was successful in terms of both safety and cost saving, and Network Rail is already considering rolling out a plan to renew the DC switchgear on the network.
“RPS, BAM Nuttall, and Network Rail worked collaboratively and innovatively together – the Dollands Moor Switchgear project was a great success.” Network Rail project manager, Daniel Lea.
Rail Power Solutions is a specialist design and consultancy service for DC electrified railways, undertaking complex multi-disciplinary designs. Established in 2013, Rail Power Solutions has grown rapidly as the leading design consultancy for railway electrification systems, with extensive knowledge and experience in Network Rail, London Underground, London Overground, Docklands Light Railway, Merseyrail and Glasgow Subway.
In mid-2021 Lowery secured two significant packages of electrification and plant (E&P) upgrade work from Network Rail. The project is part of the Wessex CP6 framework packages 5 and 6. Package 5 consists of three new high voltage (HV) switchgear renewals including the provision of new AC modules with other ancillary equipment. Package 6 consists of four HV feeder renewals including new pilot cabling and interface with the existing AC and DC protection systems. Both of the projects are design, procurement, and build contracts.
The HV substations to be undertaken are Hinton Admiral, Eastleigh, and Woodfidley, all fully controllable from Eastleigh Electrical Control Room. The old life-expired, oil-filled HV feeders which will be replaced are feeders F2068, F2070, F2071, and F2011, all between the Kingsworthy and Eastleigh Substations. As a principal designer and contractor for both packages, Lowery will ensure the changeover commissionings are carried out in such a way to reduce any abortive and temporary works as much as possible between both packages of work, to ensure the safety and reliability of the operational railway.
Forty-five kilometres of cable will be installed as part of the Package 6 HV feeder renewal, along with cable management systems of 7km, consisting of various Under Track Crossings with 1km of buried route through Winchester and Eastleigh station car parks, and other locations including routing through Shawford station platform, along with cable troughing and post-route cable containment. The package also contains 1600 metres of new walkway to be installed and integrated into the new cable route proposal.
The majority of the new route and walkway is to be installed on steep embankments, which is why the proposed designs and project execution are key to the successful delivery and achievement of key project milestones.
Lowery’s engineering team gained experience of housing free-issued HV and ancillary equipment as a part of the London South HV Power upgrade project, and Lowery leveraged this experience in the Package 5 procurement process for the new HV modules. Its innovative manufacturing and procurement process has saved considerable time and, most notably, cost.
The company’s in-house design team is responsible for the production of the detailed design to ensure full integration of the new and existing equipment. Complete testing of the HV modules and all pre-commissioning activities are carried out with the in-house testing and commissioning team.
Undertaking tests in the factory environment reduces the requirement of repeating these tests on-site, which significantly reduces testing and commissioning time. This innovative solution provides the client with cost savings on the main items of equipment and ensures that any problems and issues can be captured in the early days and rectified in the factory prior to site delivery.
Earlier this year, the project received two of the HV modules ahead of the programme and is awaiting completion of the civil works following successful land access arrangements. All of the HV modules will be fully tested at the integrator’s premises prior to delivery to the site.
As noted, Lowery’s in-house design and engineering team is undertaking all of the electrical designs, ensuring a complete approach to prevention through the engineering and design process (formerly Safe by Design) including full self-assurance of the produced designs by the CEMs and CREs employed by the firm. As a principal designer, it is leading from the early stages of outline designs right up to the detailed design and issue for construction in line with the GRIP process, which was used before the PACE process was introduced by Network Rail. It is utilising its trusted civil design house to undertake the civil design element for this project.
Lowery’s innovative approach to design solutions at the Hinton Admiral location, as part of the Package 5 works, has seen the scope of work increase from a new HV Switchboard renewal to a full substation upgrade including the installation of the new Rectifier Transformers with Rectifier modules and Powerbond DC module, which was added by Network Rail to the current trial for the implementation of the safer isolation process with an integrated DC switchboard and NSCD equipment.
Following the successful delivery of key projects such as the Reading 10 Car project, Euston Station High Speed 2 enabling works HV substation (Barnby Street Substation), and the London South Power Upgrade Project (Rotherhithe Switching Station) all safely and successfully delivered on time the company continues to enhance its reputation as the go-to supplier for all HV traction and non-traction project delivery.
Gary Trearty, Lowery Engineering Manager, says: “This is another exciting project for Lowery to be delivering on behalf of Network Rail and shows the confidence that companies have in Lowery’s ability to continually deliver complex design and build projects on the Railway infrastructure, safely, on time and under budget.”
As always Lowery looks forward to working with new and of course our existing clients to successfully deliver all types of complex projects, safely and collaboratively.
As part of the valuable debate on electrification, the Railway Industry Association (RIA) arranged a presentation on electrification delivery in late February, concentrating on the need to achieve a realistic and acceptable cost of installation and commissioning.
The presenters were Philip Doughty, chief mechanical and electrical engineer at Network Rail and Peter Dearman in his pan-industry role. The session took account of the Covid restrictions at the time with both physical and online attendance. The hybrid session was well-managed by RIA’s staff.
Stop and start
In a striking and hard-hitting opening session Peter Dearman reminded those present that there had been a history of stop and start on electrification within the UK. Notwithstanding the Weir report recommendations before the second world war, there had been an important strategic aim delivered in 1955. This led to the delivery of the West Coast route electrification, albeit in phases.
A major plan was put together by British Rail in the late 1970s which recommended virtually complete system electrification and it was noted that on that basis their recommended network would have been electrified by 2004. A further major push occurred in 2010 with the National Electrification Plan but, by the end of the decade, full system electrification was still not on the horizon. Now we have the Traction Decarbonisation Network Strategy which yet again delivers a chance to go forward with that goal of a majority electrified system.
Peter delivered a warning that, after the history of the last few decades, this really was probably the last chance of gaining acceptance of major system wide application of electric traction and the industry must not fail to get it right. Other transport modes were reacting to the need to decarbonise and rail could be left behind in search for a robust, environmentally friendly transport system. In summary, there are around 13,000 single track kilometres of electrification which can be justifiably equipped.
Philip Doughty took over the lead and emphasised how Network Rail was reacting to the challenge of bringing the cost of electrification down to acceptable levels and was at pains to point out that all options were on the table. Standards could be challenged and how requirements could be applied would be analysed with a view to compliance at an optimum cost.
The first area Philip mentioned was the height of bridge parapets on electrified lines. The audience were reminded that the impact of the extra weight loading imposed could be quite significant; even possibly leading to a need to reconstruct where the structure was at a margin. The need to reduce the risk was recognised but the application of robust risk assessment practices and some original thought could lead to major savings.
Clearances from live equipment had always been a challenge within high-voltage railway electrification, particularly on UK systems with their tighter gauge, and major developments had taken place leading to significant economies. However, there were further opportunities to be examined and basic definitions to be reviewed. The current standards referenced the distance from a standing surface, but that definition of the surface required some refinement and common sense in application, recognising that any standing surface must be assessed on the basis of anyone credibly standing on it.
Other targets for development included the adoption of insulated pantograph horns in the UK as accepted in the rest of the continent. Wire gradients and mast spacing were also in the sights. Additionally, the application of ground-proving radar could reduce the need for trial holes and, on a basic level, the whole range of masts could probably be rationalised.
However, other upward impacts on cost could be driven by factors other than physical works and challenges of process, and non-design and non-construction resources, were to be given consideration. The headcount of ‘white collar’ staff against active staff on the ground was an area ripe for action to reduce the headcount.
In the light of the UK’s economic position, all infrastructure developments are the subject of close scrutiny by the government, in particular the treasury. Comparison will be made with practice elsewhere and those comparisons are not always positive, however studies show that costs can be brought under control and limited with a rolling programme, in a highly effective fashion. Philip pointed out that the highways authority has a rolling programme, coupled to alliancing arrangements, for smart motorway rollout and that this has had very positive financial effects. He noted that Germany has a consistent rolling programme of electrification on an annual basis and their costs are significantly better than those of this country.
A fresh approach
Discussion then moved over to other potential physical design and construction impacts. The subject of discontinuous electrification came up and Graeme Brindle demonstrated how this was being considered on the South Wales electrification scheme. Where there were severe infrastructure challenges or even overly complex locations, application of the philosophy was being considered. The discontinuities could always be removed later in the life of the infrastructure; for instance, when a bridge renewal came due in future years.
Freight traffic was becoming an increasingly focussed area and it was noted that discontinuous electrification did not sit well with single locomotive haulage. The potential modal shift would require a fresh approach to not only electrification but operation and general railway construction and design issues.
Although the emphasis was on electrification, it has been accepted that there are parts of the network which will possibly never justify full conventional electrification and pragmatic approaches to battery and hydrogen traction sources were accepted as part of the mix. Similarly bi-mode diesel electric could also find a place; particularly where installation of electrification contact and distribution systems could not be installed on an all-line basis initially.
The last chance
Overall, the Group meeting produced a very positive and realistic vehicle for taking electrification forward although both Philip and Peter were at pains in their summing up to emphasise that this was really the last opportunity to get it right and that the industry must accept this and make system electrification a success.
RIA is to be congratulated on facilitating these group discussions and enabling the railway community to be felt and heard both in society but also in government.
Recent events in Europe and the Government’s ‘Cyber Security Breaches Survey 2022’ report have reinforced the importance of good cyber security measures for all companies and organisations. Rail Engineer recently met up with Paul Burbridge, detective sergeant at the British Transport Police (BTP) Cybercrime unit, to discuss how the rail industry can better defend itself from cybercrime
The Government’s report covered all UK industry and identified that 39% of businesses identified at least one cyber-attack on their operations in the last 12 months, with phishing attempts the most common threat, reported by 83%. Cyber phishing is when attackers attempt to trick users into doing ‘the wrong thing’, such as disclosing security information such as passwords or clicking on a harmful link that will download malicious software (malware).
More sophisticated cybercrime types, such as a denial of service (DoS) or ransomware were reported by 21% of businesses. DoS is an attack designed to shut down a device or network by flooding the victim with traffic, while ransomware is a type of malware that threatens to publish the victim’s data, or lock access, unless a ransom is paid. Despite its relative low prevalence, organisations considered ransomware as a major threat, with 56% cent having a policy not to pay ransoms.
One in five businesses and 19% of charities say they experienced a negative outcome as a direct consequence of a cyber-attack, while 38% experienced at least one negative impact. Thirty-one percent of businesses and 26% of charities estimate they were attacked at least once a week.
The government guidance – ‘10 Steps to Cyber Security’ – has been designed to break down the task of protecting an organisation into 10 key components. The survey found that 49% of businesses and 40% of charities have acted in at least five of these areas. Access management came out as the most proactive, with supply chain security the least proactive in implementing defences to cybercrime.
The survey also showed that 54% of businesses have acted in the past 12 months to identify cyber-security risks, with the risk often passed on to outsourced cyber providers, insurance companies, or internal cyber colleagues.
It is a concern that the 2022 survey says that there remains a lack of both will and skill around organisational cyber security, resulting in gaps in “some more fundamental areas of cyber hygiene”. Fewer than one in five businesses have a formal incident management plan; there is a lack of technical knowhow expertise within smaller organisations and at senior level within larger organisations – despite cyber security being seen as a high priority area, and investment in cyber security is still largely viewed as a cost rather than an investment. Therefore, many organisations rely on a reactive approach to cyber security instead of proactively driving improvements.
While the number of reported attacks is a consistent figure in recent years, the survey also noted that enhanced cyber security can lead to higher identification of attacks, suggesting that some less cyber-mature organisations may be under-reporting threats. BTP suspects under reporting of cybercrime may be the case in rail and Paul said “I urge anyone who may have had a cyber-attack to report it to us. We can then provide advice and help and build up an accurate picture of the cyber threats to rail.”
“We also have excellent links to other UK government experts in cybercrime along with international law enforcement organisations. Not reporting a cyber security incident can lead to what may appear to be a ‘non-loss’ situation developing into a major problem if it is not properly and thoroughly investigated.”
Rail at risk
During the early stages of the Russo-Ukraine crisis, it is reported that railway workers, hackers, and dissident security forces disabled or disrupted the railway links connecting Russia to Ukraine through Belarus, disrupting supply lines. In January, a group calling themselves Belarusian Cyber-Partisans carried out a ransomware attack on the Belarusian state railway network, encrypting the data on a number of its servers. They posted screenshots online to illustrate the level of access they had obtained.
The group claimed to have attacked many of the railway’s ‘automated systems’ and that they had the capability to alter the function of the railway’s automatic route setting software. There was evidence reported that significant disruption was caused. Following the invasion, the group announced a further cyber attack and Belarusian railway websites were confirmed to be down for some time. Social media showed long queues of people for tickets several days after the incident.
The Financial Times reported that US cyber security experts had reduced the potential for attacks as part of their pre-emptive cyber defence work for Ukraine. One particular type of malware called Wiperware was found on the Ukrainian Railway’s servers. Unlike ransomware, and other common malware, Wiperware is not focused on theft or financial gain. It is purely destructive and is designed to significantly damage systems by erasing data and programs, with no way of restoring them.
In March, Reuters reported that the Italian railway company Ferrovie dello Stato Italiane (FS) had temporarily halted some ticket sales as it believed it had been targeted by a cyber attack. “Since this morning, elements that could be linked to a crypto locker infection have been detected,” the company said. FS went on to say it had suspended the sale of tickets at its offices and self-service machines in train stations as a precautionary measure, while online sales were working as usual. The disruptions did not impact rail traffic, which was running smoothly, FS added.
Attacks like the ones reported may lead to escalation, which increases the risk to other railways. Previous major cyber-attacks, such as Stuxnet and NotPetya, led to the spread of cyber viruses and the copying of techniques by new attackers. The rail industry therefore needs to examine the recent incidents as examples of cyber-attacks to rail that could be repeated by others.
There is lots of advice and good practice of cyber security available from organisations such as the National Cyber Security Centre. Steps that should be considered include addressing cybersecurity at the earliest stage of any project as attempts to retrofit security solutions will almost certainly fail; carrying out a regular threat analysis considering both internal and external threats to security; and defence in depth – cyber security should be implemented in layers using a wide range of solutions to provide monitoring and defence across and throughout the organisation. This should include protection from physical attack by using proven secure locking systems to protect communications cables and ports, equipment rooms, and equipment cabinets in rooms and on rolling stock. Access to equipment must only be given to competent, trusted maintainers.
Organisations must also use recognised good security management practice, such as the ISO/IEC 27000 series of standards, and implement physical, personnel, procedural and technical measures. They should implement simple measures, such as instructing everyone not to use USB drives or click on any links from outside the business without checking they are safe.
Cyber security should be implemented using a quality assurance system based on: requirements capture – specify – development – design – implement – maintain – test. Every organisation should also be tested on a regular basis, ideally by an independent third party.
Many businesses and organisations lack the will and skill for good organisational cyber security, resulting in gaps in “some more fundamental areas of cyber hygiene,” according to the government’s report. Cyber attacks in other countries suggest that cybercrime is a risk to UK rail. However, solutions and tools are available and cybercrime is another challenge that railways must rise to. All instances of rail cybercrime must be reported to BTP, who are ready to investigate, help and advise.
Organisations or businesses who need to contact BTP can contact the Pursue team at [email protected]. If you are a rail company or part of the railway supply chain and experiencing a live and ongoing cyber-attack, please contact the BTP control room on 0800 405 040.
HS2 reached a major milestone on 31 May as construction on the railway’s first and longest viaduct began. Stretching for more than two miles across a series of lakes and waterways between Hillingdon and the M25, the Colne Valley Viaduct will also be the longest railway bridge in the UK.
The event was marked with the launch of an enormous 700 tonne bridge-building machine at an event attended by the HS2 Minister, Andrew Stephenson MP, just outside London.
“Today, HS2 began construction on what’s set to be Britain’s longest railway viaduct,” said Mr Stephenson, “a landmark moment for HS2 and a feat of British engineering, taking the HS2 line from London, and into Hertfordshire and Buckinghamshire.
“Infrastructure is the backbone of HS2 and this viaduct will be integral to delivering faster journeys and an increased capacity rail network.”
One of a kind
Known as a ‘launching girder’, the 160-metre-long bridge-building machine is the only one of its kind in the UK. Originally built in 2004, the launching girder was first used during the construction of the Hong Kong East Tsing Yi Viaduct. Specially designed to handle complex viaduct construction, the machine is named ‘Dominique’ in memory of Bouygues engineer Dominique Droniou who played a leading role in its design and development.
The machine will lift the giant concrete deck segments that form the viaduct’s arches into position. Once each section is complete, it will inch itself forward into position to build the next stage.
A total of one thousand deck segments will be needed, with each one weighing up to 140 tonnes. To allow for the gentle curves of the viaduct as it crosses the valley, all the segments are slightly different shapes and made on site at a purpose-built temporary factory close to the north abutment.
“I’m absolutely delighted that we have started work to assemble the giant deck segments that will form the Colne Valley Viaduct,” said HS2 Ltd Chief Executive Mark Thurston. “It is yet another big milestone for HS2 Ltd, as we work to deliver the UK’s new high-speed railway. Once complete, this record-breaking structure will form a key part of the HS2 railway − helping to deliver better connections across the UK, free up rail capacity on the train network, and offer passengers a zero-carbon travel option.
“I’d like to thank all those involved in getting us to this exciting stage and look forward to seeing the whole viaduct come together over the coming years.”
Collaboration and teamwork
The viaduct project is being led by HS2’s main works contractor Align JV – a team made up of Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick.
Fifty-six piers, each weighing around 370 tonnes, are being constructed along the Colne Valley ahead of the girder, with the girder moving from one pier to the next, installing the deck segments as it goes. One segment is put in place each side of the central pier, using a cantilever approach to balance the structure, as two half-arches either side of each pier are constructed simultaneously. Steel tensioning cables will be threaded through the segments to strengthen the bridge.
Every segment will be a slightly different shape depending on where it fits into the viaduct and the modular approach was chosen to ensure quality, safety, and efficiency.
The viaduct pre-cast factory where the segments are made at the peak of construction will cast around 12 segments every week using a ‘match-casting’ technique. This approach − where each segment is poured against the previous one – will ensure the whole deck fits perfectly when assembled on the piers. The mammoth 100m long viaduct precast factory, which is visible from the M25, has an internal volume of 105,000 cubic metres − making it larger than the Royal Albert Hall.
Once construction is complete, the factory and surrounding buildings will be removed and the whole area between the viaduct and the Chiltern tunnel will be transformed into an area of chalk grassland and woodland as part of HS2’s ‘green corridor’ project.
“The start of the erection of the deck segments marks the latest important milestone for Align, relating to the construction of the Colne Valley Viaduct,” said Align Project Director, Daniel Altier.
“There has been a lot of hard work involved to get us to this point, and the achievements so far are a great example of what collaboration and excellent teamwork can deliver. I would specifically like to acknowledge the contribution from our supply chain partners − VSL, Kilnbridge, KVJV, VolkerStevin, Tarmac, Sendin and Vaughan Plant Haulage.
The design of the Colne Valley Viaduct was inspired by the flight of a stone skipping across the water, with a series of elegant spans, some up to 80 metres long, carrying the railway around 10 metres above the surface of the lakes, River Colne and Grand Union Canal.
Set low into the landscape, wider spans will carry the viaduct as it crosses the lakes, with narrower spans for the approaches. This design was chosen to enable views across the landscape, minimise the viaduct’s footprint on the lakes and help complement views across the natural surroundings.
In another visible sign of progress on the project, the team has also completed the construction of three of four jetties across the lakes to get equipment into position to support the construction and help take construction vehicles off local roads. Where the viaduct crosses the lakes, the piles are being bored directly into the lakebed, using a cofferdam to hold back the water while the pier is constructed.
Construction has started at the site of HS2’s first innovative ‘green tunnel’, designed to blend the high-speed railway into the landscape and reduce disruption for communities.
Unlike a normal underground tunnel, the one-and-a-half mile Chipping Warden green tunnel in Northamptonshire is being built on the surface using a pioneering off-site manufacturing approach to speed up construction and improve efficiency.
This approach will see more than 5,000 giant concrete tunnel segments made in a factory in Derbyshire before being assembled on site. The completed tunnel will then be covered by earth, with trees, shrubs and hedgerows planted to fit in with the surrounding countryside.
Chipping Warden is one of five ‘green tunnels’ that are being built on phase one of the HS2 project, which is designed to improve links between London, Birmingham, and the north, to help level-up the economy, and provide a low carbon alternative to car and air travel.
Applying lessons from the construction of the latest French high-speed lines, the off-site approach was developed by HS2’s main works contractor, EKFB − a team made up of Eiffage, Kier, Ferrovial Construction and BAM Nuttall. The tunnel segments are being made by Stanton Precast in Ilkeston Derbyshire as part of a contract which is set to create up to 100 local jobs.
“The Chipping Warden green tunnel is a great example of what we’re doing to reduce disruption for people living close to the railway,” said HS2 Ltd’s Project Client Rohan Perin, “and it’s fantastic to see the first arches in position. “Our trains will be powered by zero carbon electricity but it’s also important to reduce the amount of carbon embedded in construction. The off-site manufacturing techniques being used will help cutting the overall amount of carbon-intensive concrete and steel in the tunnel and make the whole process faster, more efficient and therefore less disruptive for the community.”
Designed as an m-shaped double arch, the tunnel will have separate halves for southbound and northbound trains − each one the height of two double-decker buses. Instead of casting the whole tunnel on site, five different concrete precast segments will be slotted together to achieve the double arch − one central pier, two side walls and two roof slabs. All 5,020 segments will be steel reinforced, with the largest weighing up to 43 tonnes.
Concrete and steel are some of the biggest sources of carbon emissions within the construction industry and by reducing the amount of both materials needed for the tunnel, this lighter-weight modular approach is expected to more than halve the amount of carbon embedded in the structure. It also requires less people and equipment on site, improving safety and reducing disruption for residents.
“Seeing the first set of precast units being installed is a milestone that the whole team is very proud of,” said EKFB’s Project Manager, Jeremie Martin. “This three-year construction programme will benefit from off-site manufacturing making the green tunnel build more efficient than the traditional on-site building method.
“The HS2 green tunnels are a first of its kind in the UK. We have designed them as a twin arch ‘M’ shape which is more efficient than the standard box structure, reducing the amount of concrete required, which is a great example of how innovative engineering design can reduce carbon impact.”
The tunnel will be built in sections, with construction expected to be complete in 2024. A relief road has also recently been completed, which will take HS2 vehicles – and other local traffic – away from the centre of the village of Chipping Warden. This will later be extended, to take the A361 over the top of the green tunnel.
Similar green tunnels will also be built at nearby Greatworth as well as Wendover in Buckinghamshire and Burton Green in Warwickshire, stretching for a combined total of more than four miles. The tunnels will all have specially designed ‘porous portals’ at either end to reduce the noise of trains entering and exiting the tunnel, along with small portal buildings to house safety and electrical equipment.
Tailored landscaping design plans will be developed for each tunnel, with thousands of native trees and shrubs typical to the local area such as Silver Birch, Oak, Beech, and Willow planted to create new woodland areas around the portals and recreate the hedgerows and field boundaries on top of the tunnel.
All 13,290 segments for Chipping Warden, Greatworth, and Wendover are being made by Derbyshire-based Stanton Precast Ltd, in a deal that is set to create up to 100 jobs at their Ilkeston factory − an increase in their workforce of around 50%. New production sheds, casting and storage areas are also being built at the factory to accommodate the new work.