Research in progress
Conductive sand alternatives show promiseEnabling assisted braking and door operation systemsBetter modelling of the relationship between safety and performanceImproving our understanding of freight train braking in low-adhesion conditions
Reducing the insulating effects of sand used in low-adhesion conditions can improve safety and allow higher laying rates.
Sanding is vital to keep trains running safely in low-adhesion conditions, particularly during autumn. But natural sand is an electrical insulator. Too much sand increases the risk of a train going undetected by the signalling system, known as a wrong-side track circuit failure (WSTCF). Therefore, limits are set on how much sand is applied to the tracks.
Conductive sand alternatives have higher electrical conductivity. They aim to create a more robust electrical contact between train and track. If demonstrated to be effective and put into use, they would reduce the sand being applied.
Earlier lab and field tests by the University of Sheffield found that some commercial products showed promise for non-electrified routes that suffer from contamination. However, they needed further testing to check their performance during braking at speed.
Two products were tested at Tuxford Rail Innovation and Development Centre under controlled low-adhesion conditions. The testing took place in partnership with South Western Railway and DB ESG. Class 158s fitted with new single variable-rate sanders deployed the product while braking from 50 mph. From the emerging findings, one product compares favourably with natural sand in terms of braking performance in low-adhesion conditions, while providing the conductivity to avoid WSTCFs.
We are now working with Northern on an operational trial of this sand alternative in autumn 2024.
Keep up to date with the research at rssb.co.uk/research-catalogue (search for COF-UOS22-03).
For more information about the findings of the full-scale testing and to discuss running an operational trial, contact Paul Gray, Professional Lead, Engineering:
Paul.Gray@rssb.co.uk
Partial automation could help drivers position the train correctly every time.
Assisted braking and door operation (ABDO) is a new concept for passenger trains. It aims to provide some of the benefits of automatic train operation without all the associated costs. The driver keeps full control of the train, but the system assists the driver by braking on approach to timetabled station stops.
Station overruns and short stopping put passengers at risk if the doors are released when they not aligned with the level platform. Even if the driver realises the error in time, delays may occur while they liaise with the signaller to reposition the train. These delays can result in signals being held at danger, increasing the signals passed at danger (SPAD) risk to other services. They may also result in impatient passengers self-evacuating, causing wider safety and performance issues.
ABDO makes overruns and short stopping less likely. South Western Railway (SWR) and Alstom have been developing ABDO as part of the introduction of the Class 701 fleet. The system:
detects when the train is approaching a station
calculates the braking force required to stop the train in the correct position
applies the brakes accordingly.
The driver stays in control and can apply further braking force or override the system, if necessary.
The system will be undergoing non-passenger testing on some of SWR’s Class 701 fleet to determine its technical suitability for in-service operation. Although there are currently no plans for widespread use of ABDO, this is an opportunity to consider how its introduction would impact the railway and how it could be successfully introduced operationally.
Our research is therefore looking at the benefits and challenges of ABDO. It will also consider how existing rules and standards might change to support its introduction
A second phase of the research, co-funded by Network Rail, is currently underway to improve and further test the PoC. It will also identify the steps needed to take the system from a PoC to a trial-level version.
Keep up to date with the project at rssb.co.uk/research-catalogue (search for T1326).
To discuss the research, contact Marcus Carmichael, Professional Lead, Operations and Performance:
Marcus.Carmichael@rssb.co.uk
An updated and enhanced model will help operators quantify knock-on risk.
Slowing or stopping trains reduces direct risks. But it may increase bigger-picture safety risks, such as overcrowding in stations or signals passed at danger (SPADs). RSSB previously developed a simple model to quantify such knock-on risks. This model helped inform some high-profile safety decisions, such as the rules for GSM-R radio failures and responses to extreme rainfall. However, the analysis behind the model is now out of date.
Our research will update the model to include post-COVID-19 data. It will also draw on larger and more detailed datasets. Users will be able to analyse relationships in more detail, for example, by service group and hour.
The work will provide a more complete view of the relationship between safety and performance. Infrastructure managers and TOCs will be able to address performance issues while taking the impact on overall risk into account.
For example, the model will help industry determine the knock-on risks from service alterations or the safety impact of passenger behaviour during major incidents. The model will also shed more light on the complex interplay between knock-on effects and delays. To what extent do SPADs cause delays, and to what extent do delays cause SPADs?
The updated model will feed into future updates of decision support tools. These include the Safety Risk Model and the Proportionate Risk response to Implementing Mitigating speeds to Assets (PRIMA).
Keep up to date with the project at rssb.co.uk/research-catalogue (search for T1344).
To discuss the project, contact Liz Davies, Professional Lead, Data and Modelling Research:
Liz.Davies@rssb.co.uk
Greater awareness of freight braking technology, practices, and processes will inform future research.
Investigations into recent freight train derailments have raised questions about the effectiveness of braking systems. For example, a 2022 freight derailment at Petteril Bridge Junction, Carlisle, damaged the track and disrupted services for seven weeks. The RAIB report included the recommendation ‘to understand and manage the risks associated with the operation of freight trains in low-adhesion conditions’.
Various research questions looking at freight train braking have been proposed. To establish a baseline understanding of braking capabilities and practices to support future research, we are carrying out a knowledge search.
The scope of the work includes:
the types of locomotives and freight wagons running on the GB mainline
key features and parameters relevant to braking of that rolling stock
technical details of current locomotive and freight wagon brake systems
what monitoring is available for freight train braking, and whether enhanced monitoring could bring new insights.
The completed knowledge search (S386) will be available to download at rssb.co.uk/research-catalogue.
To discuss and contribute to this work, please contact Paul Gray, Professional Lead, Engineering: