Case studies
Colour vision requirements for train drivers (T1279)
Revision to the W10 and W12 freight gauges (T1327)
Piloting double variable rate sanders on the GB mainline (IMP-T1107)
A common social impact framework for rail (T1127)
Inerters: From early feasibility to prototyping and testing novel components
Being able to see and distinguish colours is an important requirement for many safety-critical roles on the railway. The standard Ishihara test is commonly used to screen for colour vision deficiency. However, this test is not precise. It detects that somebody may have colour-deficient vision but not the specific degree of the deficiency.
Current and potential rail employees with minor colour deficiency may fail the test, even though they could safely perform the role.
Previous medical standards allowed a secondary test for anyone failing the Ishihara test, but there was no guidance on the secondary test.
RSSB’s research, delivered by City University, proposed a two-step approach to colour vision assessment. The Ishihara test would be the primary screening test. However, anyone who failed would take a Colour Assessment and Diagnosis test to determine the specific degree of their colour vision deficiency. The research defined pass or fail thresholds that exclude only those with colour deficiency that would impair their ability to perform the role safely.
Analysis suggests that the new approach will enable a significant number of railway staff who currently fail the Ishihara test to be assessed as safe to perform the role.
The findings of this research have informed changes to rail industry standard RIS-3789-TOM, published in March 2025. The revised standard is being used by Govia Thameslink Railway (GTR), where it has already helped five drivers return to work.
We are grateful to the train drivers at GTR who have been a driving force behind this project, and to RSSB [….]. As a result of this project, we are now formulating plans to help our drivers get back to the front of trains, doing what they love.
The new testing regime will help reduce costs and alleviate driver shortages—and, of course, it is great news for individuals affected by mild colour vision impairments.
Railway gauging refers to the size of the cross-section of the train relative to the infrastructure around it. Simply put, gauges ensure that trains do not hit structures such as bridges, platforms, and buildings.
Depending on the type of train, different types of gauging are used. The W10 and W12 gauges are used for freight wagons and containers on the GB rail network. W10 focuses on narrower containers, while W12 provides additional width clearance for larger cargo.
These gauges were designed around wagon and container combinations on the network in 2002. They do not cater for some newer wagons.
The research reviewed W10 and W12 to find extra space in these gauging envelopes to allow more combinations of wagons and containers to run. The cross-industry Vehicle/Structures System Interface Committee, freight operators, and Network Rail came together to explore options, evaluate trade-offs, and make the case for change.
The analysis led to revised W10 and W12 gauges that fit more vehicle combinations. For W10 and W12, a further 64 and 151 container/wagon combinations can be added, respectively. The changes proposed by the research also opened more routes to these two gauges, increasing freight’s network access.
The research will be incorporated into an update of Railway Group Standard GERT8073. In advance of the publication of the revised standard, freight operators Freightliner and DB Cargo have asked for the new gauging tables to be published to allow early adoption.
See current and new potential routes overleaf.
The retrofitment of single variable-rate sanders to SWR’s Class 158 and Class 159 fleets have so far been one of the most effective modifications to improve braking capabilities in low adhesion conditions. Early results show a reduction in low-adhesion slide incidents and improvements in operational performance in autumn.
With double variable-rate sanders now in service on the Class 323s, we have seen improvements in braking capabilities and operational performance on routes that routinely experience low adhesion conditions.
The risk posed by low adhesion can be catastrophic, as the train collision at Salisbury in 2021 proved. Variable-rate sanders apply more sand to the wheel-rail interface at higher speeds, significantly improving braking in low-adhesion conditions.
The findings on variable-rate sanders came from early lab-based feasibility studies, followed by a comprehensive 3-month programme of track testing on Class 387s during 2019. Better braking performance is achieved from one variable-rate sander (single variable-rate sander, or SVRS) in operation on short train formations or, where space and train length permits, two sanders (double variable-rate sanders, or DVRS). An in-service pilot with West Midlands Railway confirmed the results. This paved the way for retrofitting variable-rate sanders to existing rolling stock and incorporating them into new designs.
South Western Railway and Porterbrook (a rolling stock company) retrofitted SVRS to 39 units from their Class 158 and 159 fleets in time for autumn 2024. Recognising that autumn conditions vary every year, there were three reported low-adhesion slide incidents in 2022 and four in 2023. In 2024, with the new sanders, there were none.
Northern, also working with Porterbrook, has retrofitted DVRS to its Class 323 fleet. The whole fleet (34 units) has been fitted, and the sanders were in service for autumn 2024. There were no reported low-adhesion slides for the Class 323 fleet.
An RSSB research project set out to create a common framework for the rail industry to baseline, measure, monitor, and evaluate social impacts across Great Britain’s rail industry.
By establishing a common framework for measuring social impacts, the research addressed inconsistencies and lack of trust in existing metrics. The insights and methodologies developed through the research were integral to the creation of the Rail Social Value Tool (RSVT). The RSVT is now well established and used by the rail industry to quantify and enhance its social value.
At Avanti West Coast, we have been using the RSVT for nearly 3 years and we are starting to reap the benefits. It allows us to constantly document and calculate our social value impact, allowing for year-on-year growth towards our target of £1 billion social value impact.
Social value impact is an ever-evolving topic. The fact that we can contribute directly to the development of the RSVT allows us to be at the forefront of social value impact measurement in the rail industry, ensuring the upliftment of the communities we serve.
An inerter is a passive mechanical device that produces a force proportional to the relative acceleration between its ends. In a vehicle suspension, it can result in improved control of vehicle behaviour to reduce track and wheel wear.
Inerters were invented and used in on Formula 1 cars. RSSB’s initial technology transfer exercise identified potential applications of this technology in rail. This triggered a range of organisations to start making progress in three out of the four applications identified.
The table to the right summarises the overall progress to date for the applications of the inerter technology in rail.
Application of inerter technology to rail
Status
Expected benefits
Primary suspensionin passenger trains
In-service trials planned during 2026
£20 million reduction in fleet maintenance costs over 10 years, plus lower rates of track wear
Secondary suspension in passenger trains
Commercial studies underway
Not quantified
Pantographs
Prototype design complete
40% reduction in contact forces
Freight suspension
Not started
RSSB research continues to play an important role in developing inerters for primary and secondary suspension.
In particular, the work on primary suspension recently culminated in the successful prototyping and testing of an enhanced trailing arm bush (ETAB) for MK4 rolling stock. We are now working with Transport for Wales for ETAB to go through the assurance process and be used in the refurbishment of the MK4 fleet planned for November 2026.
An excellent indicator of implementation potential is the level of involvement by stakeholders. In this case, as the research journey moved from modelling and design to prototyping and testing, a range of stakeholders have been providing significant support, including financial (ROSCOs) and in-kind (GMT, the bushing manufacturer that prototyped the design) contributions.
