Defective on-train equipment

The requirements for managing defective on-train equipment have been comprehensively reviewed and the resultant changes should help cut the number of passenger trains terminated short of their destinations, while not adversely affecting the overall level of risk.

Following a proposal to review Rule Book module TW5 and RIS-3437-TOM, Defective On-Train Equipment, and its associated guidance (GOGN3637) for operation of trains following use of the emergency bypass switch (EBS), the Traffic Operation and Management Standards Committee (TOM SC) decided to extend the scope of the review to include a number of other items including the automatic warning system (AWS), driver’s safety device (DSD) (and vigilance equipment) and the train protection and warning system (TPWS).

Using a similar risk review process to that which had recently been used to determine the arrangements for defective GSM-R train radio, data from the Safety Risk Model and Safety Management Intelligence System (SMIS) was used to assess the safety risk associated with different responses to defective AWS, TPWS and DSD. The initial results were reviewed and refined through a series of five risk analysis workshops with industry representatives.

For AWS, DSD and TPWS defects, it was concluded that the total network risks could be minimised by allowing passengers to remain on the train for up to 100 miles and at a maximum speed of 60 mph rather than 40 mph. The basis for this is that the resulting risk to the failed train (travelling up to 100 miles) – and to other trains on the network – is less than the secondary risks associated with passengers alighting from the defective train and joining another. With defective AWS and DSD, the higher speed allows the maximum protection from the overspeed element of TPWS to be retained.

For freight trains, the maximum travelling speed with AWS, DSD and TPWS defects was changed to 50 mph following feedback as industry representatives felt that 60 mph could cause additional risks for Class 6 freight trains (for which 60 mph is their normal maximum speed) and at 50 mph freight trains retain the same level of TPWS protection as passenger trains do at 60 mph.

The opportunity was taken during the project to revise instructions regarding defective doors to reflect the fact that many new trains are now, internally, effectively a continuous tube, with little or no ability to secure individual vehicles out of passenger use. Consequently, the revised arrangements consider the effect of a defective door on the train as a whole and the distance an individual passenger might now be from an available emergency exit.

Prior to the review it had become apparent that the terms ‘entering service’ and ‘when in service’ were not always understood to have the meaning shown in the Rule Book Glossary. Consequently, these terms have been changed to ‘starting a journey’ and ‘during a journey’ to improve clarity and understanding.

The other findings from what was a thorough review of the arrangements for defective on-train equipment are now reflected in Rule Book modules TW5 issue 9 and AC issue 5, and updated Rule Book Glossary, as well as in RIS-3437-TOM Defective On-Train Equipment issue 2 which incorporates guidance previously shown in its separate guidance note GOGN3637.

RIS-3437-TOM issue two will be issued and its requirements available to be applied from 01 September 2018. However, some of the changes cannot be implemented until Rule Book module TW5 issue nine becomes operative in December 2018. 

The resources on this page are designed to help train operators in updating their contingency plans and frontline staff in understanding changes to arrangements for defective on-train equipment in Rule Book modules TW5 and AC. Full details of all the changes can be found in the Impact Assessment which accompanies RIS-3437-TOM and TW5 in the RGS catalogue for September 2018. 


Log in or register to keep reading
Register for free individual access
  • Unlock research, articles and more
  • Get updates on RSSB’s activities





Need some help?
To talk to us about accessing RSSB content or corporate membership:
Cookies help us improve your website experience.
By using our website, you agree to our use of cookies.