Work completed in 2024–25
Providing a framework for the unique identification of trains
Updating the Track Circuit Assistors Risk Adviser Tool to reflect modern fleets
Easier assessment of electromagnetic compatibility
V/TC&C SIC’s work highlighted the industry’s challenges with identifiers and led to the development of a new standard.
The lack of a unique train identification system was highlighted by VTC&C SIC. A sub-set of the committee worked with industry experts to produce a map that shows the existing train identification systems.
The map detailed the different systems and how they interface with each other.
With inefficiency and potential for safety improvement on show visually for the first time, the map helped to demonstrate the need for a new standard.
The committee was involved throughout the drafting of the new Train Service and Path Identifiers standard. Prior to the standard’s sign off by the Data, Systems and Telematics Standards Committee, we undertook a review to confirm that the issues identified in the original exercise had been addressed.
The standard has now been through industry consultation and is due for publication in September 2025.
Contact Andrew Graham, Lead Control Command and Signalling Engineer, RSSB, with any queries:
Andrew.Graham@rssb.co.uk
For the first time in GB, there will be a clear framework for the unique identification of trains. It brings many opportunities to develop technology to improve overall train performance and safety.
The tool prevents unnecessary disruption and over-specification of rolling stock while maintaining safety.
In the 1980s, Track Circuit Assistors (TCAs) were fitted to diesel multiple units (DMUs) on the GB mainline. Lightweight DMUs do not always trigger the track circuits that detect trains for signalling purposes.
These wrong-side track circuit failures are most common when there is poor contact between wheel and rail. This could be caused by rust or leaf film. The TCA induces a higher voltage at the wheel/rail interface, breaking down the contaminant and allowing track circuit current to flow.
To support safe and efficient decision-making, RSSB developed a TCA – Risk Adviser Tool. It allows train operators to assess the risk of operating specific trains over a specific type of route when TCAs are not operational. It also allows buyers and manufacturers of trains to validate whether TCAs are needed on new DMUs.
The Risk Adviser Tool was last updated in 2016. Recognising that new fleets are being planned and introduced, including some with battery trains, the Vehicle/Vehicle System Interface Committee (V/V SIC) and the V/TC&C SIC proposed that the tool be updated.
The new tool, released in 2024, continues to be an essential part of managing on-train equipment, particularly in the leaf-fall season. The updated version ensures its continued relevance for years to come.
Read the research findings in the RSSB Research Catalogue (IMP-T579).
For access to the updated tool and help with putting it to use, contact Paul Gray, Professional Lead, Engineering, RSSB:
Paul.Gray@rssb.co.uk
A new guidance note will cut the time and complexity of introducing new rolling stock.
Achieving rolling stock electromagnetic compatibility with control, command and signalling (CCS) subsystems can be time consuming and challenging.
Copper cables alongside the GB mainline railway are used to transmit audio and digital signals. Traction current from overhead or third-rail electrification results in a voltage being induced into these cables, causing electromagnetic interference. This can make voice communications difficult to hear and interrupt digital information. Due to these problems, electromagnetic compatibility must be demonstrated when introducing new or refurbished electric trains.
V/TC&C’s subgroup on electromagnetic compatibility developed a transfer function that models the ratio of transverse voltage (induced in copper telecommunications cables) to train current. This was informed by extensive rolling stock emissions measurement.
Using this model can reduce the need for time-consuming real-world testing when new rolling stock is introduced. The model can also be used by rolling stock designers because it provides constraints for propulsion systems.
Two major projects have already made use of GMGN2694 Issue 1 Rolling Stock Electromagnetic Compatibility with Trackside CCS Subsystems, the resulting guidance note. Aegis Engineering is applying this as part of the introduction process of Class 897 trains for London North Eastern Railway. HS2 has asked for it to be applied to the design of Old Oak station compound.
Read the guidance note in the Standards Catalogue (GMGN2694 Iss 1).
RSSB will seek feedback on the application of the standard from industry groups at the 12-month review that is due in September 2025.
Contact Gill Pirou, Industry Groups Manager, RSSB, with any queries:
Gill.Pirou@rssb.co.uk
