Defective On-Train Equipment

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

At the end of 2018, Rule Book modules TW5 and AC, RIS-3437-TOM, Defective On-Train Equipment, and its associated guidance (GOGN3637) for operation of trains following use of the emergency bypass switch, were updated. The resources at the bottom of this page are designed to help train operators update their contingency plans, and front line staff to understand the changes to arrangements for defective on-train equipment in the Rule Book modules. You can find full details of all the changes in the Impact Assessment that accompanies RIS-3437-TOM and TW5 in the RGS catalogue for September 2018.

Using a similar risk review process to that 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 automatic warning system (AWS), train protection and warning system (TPWS) and driver's safety device (DSD) (and vigilance equipment). The initial results were reviewed and refined through a series of five risk analysis workshops with industry representatives.

For AWS, DSD and TPWS defects, the workshops 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.

During the project, instructions about defective doors were also revised. These reflected 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 the 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. This incorporates guidance previously shown in guidance note GOGN3637.

RIS-3437-TOM issue two was issued and available to be applied from 1 September 2018. However, some of the changes could not be implemented until Rule Book module TW5 issue nine became operative in December 2018.

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