Rolling stock and infrastructure strategy update

The extent to which future rolling stock will be battery powered and the requirement for further electrification is to be defined by Great British Railways’ (GBR) Long Term Rolling Stock and Infrastructure Strategy (LTRS&IS). There have recently been various reports and events concerning rail electrification. Furthermore, the UK Government’s emerging stance of rail electrification is becoming clear. It therefore seems timely to provide an update on rail electrification. This includes the differing views of the Westminster and Scottish Governments. It also explains why the LTRS&IS must consider freight electrification and how this would benefit the passenger railway. RIA freight report In July, the Railway Industry Association (RIA) published its report ‘Growing rail freight: the need for targeted electrification.’ This report concluded that electric freight haulage must be maximised to unlock the full economic and environmental value of rail freight. Hence, this should be a focus of the long-term rolling stock and infrastructure strategy for GBR which is currently under development. This report also considers that more powerful electric freight will create more capacity for both passenger and freight services. This would help achieve the rail freight growth target as, for example, West Coast Main Line (WCML) diesel hauled intermodal services can only run at night north of Preston. The graph shows if such diesel hauled freight ran during the day, there would be five timetable clashes with 125mph passenger trains between Preston and Glasgow. This is why such diesel-hauled trains can generally only run at night as they can only manage speeds of 25mph over the northern fells which destroys rail capacity. Yet there would be no timetable clashes if freight trains could run at 90mph which is only possible with electric traction. In effect, a non-stop 90mph freight train would then behave like a stopping 125mph passenger train. Faster freight trains also offer better crew and asset utilisation with the possibility of a train making a round trip in one day. As well as creating opportunities for premium fast freight, this further facilitates rail freight growth as more traffic carried for the same fleet size. The report therefore recommends that all industry parties work together to accelerate the current ‘Faster Freight’ initiative to increase capacity on existing electrified corridors. Research from the University of Birmingham supporting this report considered various freight routes and types of locomotives and concluded that electric locomotives are the optimum long-term solution. This concluded that although bi-mode (electric and diesel) locomotives are a practical interim solution, battery-only locomotives are not a substitute for main line electrification as they have insufficient energy storage for main line freight haulage. They could, however, be used for shunting and very short trips. The report therefore recommended that a cross-industry business case should be developed for freight electrification, including targeted infill schemes where passenger electrification is not yet required. Given existing power supply limitations, the report also called for a cross-industry review to determine the interventions required to remove constraints on electric freight. RIA Senior Technical Advisor David Clarke noted that this report demonstrates that maximising the use of electric freight unlocks additional freight and passenger capacity, improves reliability, reduces costs and delivers great economic benefits. 2024 RIA report A previous RIA report – ‘A lower cost, higher performing net-zero railway’ – analysed 216 unelectrified passenger train routes. It found that 83 of these could be operated by Battery EMUs (BEMUs) without any additional electrification as they spent sufficient time under the wires to charge batteries for the unelectrified part of the route. However, such services may require increase in overhead line equipment (OLE) power supply. This report recommended that a fleet of BEMUs should be procured as soon as possible to deliver the earliest possible carbon reduction and air quality improvements as well as improving both performance and passenger experience. Another recommendation was the eventual electrification of all main routes due to the power requirements of intercity and freight services. As a result, it concluded that 28% more of the network needed to be electrified leaving 34% of the network to be operated by battery or non diesel traction. Given the interconnected nature of the infrastructure, the report recommended the adoption of a portfolio approach with a rolling programme of electrification rather than electrifying lines on a project-by-project basis. This approach would help reduce the cost of electrification by breaking the cycle of ‘boom and bust.’ It recommended a similar approach for rolling stock. Scotland’s fleet transition strategy This strategy was published in Nov 2025. It reaches the same conclusions as the RIA report as it considers that electric trains are the preferred end-state for InterCity routes with freight traffic. Where a significant electrification is required on such corridors, it proposes an interim solution of replacing Scotland’s aging HST fleet with Class 222 Meridian units to take account of the availability of finance and allow flexibility in the pace of electrification delivery to reduce disruption. It also considers that where there is no freight market, or as a transitional measure on InterCity routes, the operation of battery-electric trains can deliver the same carbon benefits as a fully electric train while significantly reducing the capital investment required in the short to medium term. Since rail powers were devolved to Scotland, the Scottish Government has delivered 587 single track kilometres (stk) of electrification in a rolling programme which has reduced the cost of electrification. This issue has a detailed report on Scotland’s strategy which explains how it considers all relevant issues. IMechE BEMU seminar Last year’s battery traction seminar organised by the Institution of Mechanical Engineers ( IMechE) also provided useful insights. This showed that battery traction is now a mature technology by considering new trains for the Dublin DART suburban service that operate beyond the wires for at least 80km; discontinuous electrification for 170 stk of 285 stk of the Welsh Core Valley lines; and a trial to replace one generator unit (GU) on a Class 802 unit with a 575kWh battery. This showed that if batteries replaced all three GUs a return run of 135km off wire would be feasible. The seminar showed how the required battery capacity is determined by traction and auxiliaries load, safety factors, cell degradation, charging rate, and restrictions on maximum charge to maximise battery life. In addition, route specific factors must be considered, such as gradients and stopping patterns. Hence, BEMUs would be route specific and so may be difficult to cascade to other services. Furthermore, it did not provide any information about the cost of battery traction. Professor Stuart Hillmansen of the University of Birmingham noted that the assessment of battery capacity requires an understanding of the physics of railway traction. He advised that the power required by a train is proportional to the cube of its speed. The seminar also considered the need for any rolling stock and infrastructure strategy to take a whole-system approach by considering freight and +100mph passenger trains as well as suburban passenger trains. The cost of batteries over the vehicle’s lifetime and all associated discontinuous electrification costs also need to be considered. CEBR’s oil price report A recent report produced by the Campaign to Electrify Britain’s Railways (CEBR) considered how GB rail operators have been affected by the current oil price crisis. This stressed that electrification is not dependant on any particular energy source and hence offers energy resilience. The report notes that the UK Government’s Department for Energy Security and Net Zero recently announced that it has a strategic policy drive to ‘Electrify Britain’ in order to to: “get Britain off the rollercoaster of fossil fuel markets and onto the clean homegrown power.” It is not clear whether the Department for Transport supports this policy in respect of rail electrification. The report concluded that, due to the high price of diesel, £1.35 billion would have been saved over the past 11 years had all passenger trains been electrified. It also notes that only 7% of rail freight is electrically powered in contrast to 74% for passenger trains. Although the report focuses on traction energy costs, it notes that an electrified railway delivers a wide range of cost efficiencies and operational benefits relative to diesel traction in addition to its decarbonisation benefit. East West Rail Having worked on the 2010 Scottish project to reopen the Airdrie to Bathgate line, which was electrified as it was built, your writer knows that such electrification costs much less than that of electrifying an existing railway. Furthermore, this does not disrupt rail or road users. Yet in 2018, the Transport Minister decided that the East West Rail (EWR) line was not to be electrified. He considered that new diesel electric, battery electric, and hydrogen electric hybrids offered the required passenger benefits and so made expensive and disruptive electrification unnecessary. Hence, the opportunity for low-cost electrification of the first part of EWR as it was built was lost due to ministerial doctrine. No published analysis ever justified the decision. It has now been found that battery technologies alone are not sufficient as EWR will have discontinuous electrification with Battery EMUs as: “…full electrification would require overhead lines to be installed along the whole length of the route and that this would be more expensive and involve more significant disruptive works to existing railway structures.” The statement again ignores the opportunity for low-cost electrification at minimal disruption of the section of EWR that has yet to be built. On the section that must be built between Oxford and Bletchley, partial electrification is proposed between Oxford Parkway and Bicester Village. Providing a 25kV power supply to this section would either require a new power supply or a 27km long 25 kV cable to the nearest electrification at Bletchley. The cost of both these options is likely to be comparable to erecting OLE between Bicester and Bletchley. The EWR consultation document proposes a service of up to five trains an hour plus freight trains. This is an intensive service for which full electrification should be considered once the higher operation cost of BEMUs have been taken into account. For example, ScotRail considers that the operational cost of BEMUs is 23% more than EMUs. Furthermore, industry sources indicate that a BEMU vehicle’s lease cost is around £150,000 per year greater than an EMU. In addition, as freight trains cannot use discontinuous electrification, slow diesel power freight will reduce the line’s capacity. Since the GW electrification, Network Rail has done much to reduce the cost of electrification including voltage control clearance technology with Siemens surge arresters which eliminates the need for many bridge reconstructions. While EWR rejects full electrification, it is ironic that Irish Rail proposes full electrification for its Cork electrification scheme as this will take advantage of Network Rail’s electrification cost reduction technology. Of all unelectrified lines in England, EWR has perhaps the strongest case for full electrification. This is due to the reduced cost of electrifying EWR as it is built, the costs of feeding OLE not connected to electrified lines, the intensive nature of its service, and techniques that Network Rail have developed to reduce the cost of electrification. Hence, EWR’s claim that discontinuous electrification provides a lower cost solution needs to be justified. Yet when Transport Select Committee member Olly Glover MP asked for submitted a Freedom of Information request asking how discontinuous electrification was justified, this was refused. Just as in 2018, it seems decisions on EWR electrification are subject to political direction rather than informed analysis. The UK Government view Rail Engineer asked the Department for Transport (DfT)’s press office for its view on electrification and whether the LTRS&IS will consider freight. Its response was that: “We are committed to decarbonising our railway, and electrification is the most effective way to do this” and that this strategy “will set out a coordinated and more cost-effective approach to rolling out new trains and electrification, to support better performance and passenger experience.” Furthermore, the DfT “will ensure that decisions on electrification take into account the needs of freight operators. Whilst few would disagree with these statements, RIA considers that a broader view is required. Its updated Electrification Cost Challenge report, published in June, argues that: “electrification should not be viewed solely through the lens of carbon reduction. This is because they also offer a lower whole-life cost, better performance, increased capacity, improved reliability, stronger energy security and a clearer path to reducing the net subsidy required to operate the network.” In its response to the Transport Select Committee’s report – ‘Rail investment pipelines: ending boom and bust’ – the Government considers that boom and bust investment is only a supply chain perception. In respect of electrification, it considers that the objective is to “progressively decarbonise rail traction in a way that maximises emissions reduction per pound of investment,” with no mention of electrification’s wider benefits. It is true that battery traction is evolving and offers significant opportunities as RIA’s 2024 report and the IMechE battery seminar show. Yet there will always be a requirement for a significant proportion of core routes to be electrified, if they are to be operated in the most efficient manner possible. However, the DfT does not share this view. Instead, it considers that: “…advances in battery and hybrid technology and discontinuous electrification approaches mean that the optimal solution will vary by corridor and network context.” Hence, it rejects the idea of a rolling programme of electrification. It considers that the lesson from previous electrification programmes is: “…not simply that continuity matters, but that whole-system integration, taking account of evolving technology is essential to achieving efficiency.” As a result, the industry is haemorrhaging electrification skills. The recent RIA report advises that there has been a 68% reduction in staff with electrification competencies between 2018 and 2025, including more than 300 redundancies after the Midland Main Line pause. This begs the question of why the DfT’s view on the electrification of core routes differs to that of Scotland, Ireland, and all other major European railway administrations. Outside Europe, India now has 99.2% of its broad gauge electrified after electrifying 40,000km since 2014. One explanation is the very real affordability constraints on capital expenditure for electrification, but this should not stop future electrification. For example, the Scottish Government’s response to limited finance is to scale back its electrification programme and spend a high percentage of available enhancement expenditure on a rolling programme of electrification as it believes this will provide a better railway by any measure. Another reason seems to be faith in developing battery technology and a desire to be seen to innovate. Yet this view fails to consider the physics of rail traction. As mentioned earlier, Professor Hillmansen advised that the power needed by a train is proportional to the cube of its speed. Hence, per tonne, a 125mph train requires almost three times the power of a 90mph suburban train. A recent RIA report has shown that only electrification can replace diesel-hauled freight trains to give them to power to increase network capacity for both freight and passenger trains. This is a benefit not mentioned in any government statements. In respect of batteries, the UK Automotive Council expects battery specific energy to increase by about 60% over the next 10 years. Hence, whilst this will increase a BEMU’s range increase off the wires, it is unlikely to significantly decrease the 4,400 route-km of core routes for which the 2024 RIA report considered full electrification to be the optimum solution. All of this begs the question of whether Shadow GBR has an engineering focus that informs UK Government pronouncements about fleet strategy and electrification. Rail Engineer asked the DfT press office this question and was advised that: “We are working with stakeholders and partners across the industry to ensure we have a credible and implementable strategy.” It is to be hoped that this will be the case, though for now it is difficult to escape the conclusion that the UK Government’s stance on electrification is the result of political decisions that don’t take account of the physics of railway traction or fully acknowledge the benefits of electric traction. This is certainly not the case in Scotland which has a fleet strategy for which the detailed rationale was explained by engineers from Transport Scotland and Scottish Rail Holdings in presentations which were the basis for our feature on Scotland’s fleet strategy. It is to be hoped that GBR will eventually benefit from such detailed analysis by having a whole system engineering focus that ensures the railway is engineered to provide its passengers and freight customers with a high performing, high capacity railway at lowest whole life cost. It is also to be hoped that GBR will have the authority to decide how best to engineer its railway. Image credit: David Shirres