Jernbaneverket has a number of rail carriages that are applied for the revision of catenaries. These carriages are diesel driven and are equipped with a personnel lift, from which the carriage can be remote operated at a limited speed. Some of the carriages were upgraded with a more powerful lift, which was also heavier than the original one.
Later on, during a teaching session, the upgraded carriage derailed during remote operation from the lift.
SNC-Lavalin was consulted by Jernbaneverket to investigate the delailment and to identify measures to secure the stability of the carriages.
SNC-Lavalin carried out an examination of the upgraded carriages and investigations of the derailment event in order to identify of the causes of the derailment. SNC-Lavalin then presented the investigation results to Jernbaneverket, including recommendations in the form of technical and operational measures found necessary to prevent derailment, including requirements were:
- Differential pressure valves
- Center of gravity of the carriage
- Setting of levelling valves
- Driving with different lift configurations
- Driving on a straight vs curved track
- Supervision during operation
- Ballasting and stability
SNC-Lavalin also identified scenarios in which the risk of derailment could be increased – and which therefore should be avoided.
Based on the thorough examination og the dynamics of this operation and investigation of the derailment SNC-Lavalin was able to provide solid prescriptions for safe and effective operation of the upgraded revision carriages.