RSSB2726 - T1143 Devices to guide derailed trains

RAIB have noted a sequence of derailment incidents over many years where the lateral excursion of the lead vehicle has been limited by engagement between vehicle and track features that were not intended for that purpose.

The most recent of these was in September 2016 at Watford Junction where the right-hand rail engaged between the traction motor and gearbox housings of the derailed vehicle and limited the deviation from the track and as a consequence reduced the severity of the impact with an oncoming vehicle.

RAIB have made recommendations to consider the use of mechanical devices or structures to guide derailed trains with the latest recommendation in recommendation 3 of the Watford report:

"3. The intent of this recommendation is to identify and assess the effectiveness of design features that provide guidance to trains when derailed, so limiting the deviation of trains from the track and reducing the risk of collision with trains approaching on other lines. This could be achieved by the retention or strengthening of features already forming part of the bogie structure, or infrastructure measures such as guard rails. It is also intended that the learning from research in this area is used to derive meaningful design requirements.

The Rail Delivery Group (RDG), in conjunction with RSSB, should:

• a.commission research into the ways in which guidance can be provided to derailed trains. This should include consideration of:

If such features, whether existing or additional, are shown to have a net beneficial effect in reducing risk by limiting lateral deviation, RDG/RSSB should:

• b.share this information with the relevant Standards Committees; and
• c.record and disseminate the design requirements with a view to their incorporation into future standards."

Previous similar recommendations made have been reviewed by industry through the Rolling Stock Standards Committee and concluded that such devices were unlikely to be practical or effective. The purpose of this study is to provide a broader, more comprehensive study with objective outputs to provide a definitive position on derailment mitigation.

4. Objectives

Devices to guide derailed trains can be split into two categories, rolling stock mounted solutions and infrastructure mounted solutions. It is proposed that the project is split into three work packages; the first two to address the two categories separately and the third to bring the findings together.