RSSB 2355 -T1119 Simulating Offset Loading of Container Wagons on Twisted Track

In the last Ten years there have been seventeen GB mainline derailments due to combinations of track geometry faults with offset (uneven) loads and/ or wagon sensitivity to derailment. Seven of these derailments of container wagons have occurred on twisted track where offset loading of containers has been identified by the Rail Accident Investigation Branch (RAIB) as a significant contributory factor. For example, it is this interaction of twisted track and offset loading which played the major role in the derailments at Reading West Junction in 2012 and Camden Road West Junction in 2013 .

Whilst no fatalities occurred in these incidents, in the case of Reading West Junction the container was ejected onto adjoining track, and therefore had the potential for a collision with a passenger train, with far more serious consequences. Following these (and other) events, the ORR's Chief Inspector sent a letter to several companies in the rail industry requesting they work collectively to address concerns about freight train derailment relating to the combinational effects of track condition, vehicle sensitivity to track geometry and asymmetric loading of containers. In response to this request the Cross Industry Freight Derailment Working Group (XIFDWG) was established, and includes representation from Network Rail, FOCs, RSSB and the ORR. The XIFDWG have since carried out detailed analysis to identify priority areas for research and this has directly led to the specification of this, and other, projects.

This project intends to further our understanding on risk of derailment of unevenly loaded container wagons on twisted track and assist in addressing RAIB's recommendations following the investigation of the Camden Road derailment in 2013, specifically: "RAIB 21/2014 Recommendation 2 Freightliner and Network Rail should jointly request that RSSB:

a. Researches the factors that may increase the probability of derailment when container wagons are asymmetrically loaded, and in particular:

I. sensitivity to combinations of longitudinal and lateral offsets in loads that can reasonably be encountered in service;

II. the predicted performance of wagons with high torsional stiffness along their length (using the FEA type as an example); and

III. the effect of multiple twist faults, track twist over distances other than 3 metres (as commonly specified and measured by Network Rail) and lateral track irregularities."

and

"RAIB 21/2014 Recommendation 3 RSSB should amend Railway Group Standard 'Resistance of Railway Vehicles to Derailment and Roll-Over', GMRT2141 to refer specifically to asymmetric loading, including possible combinations of longitudinal and lateral load imbalance (paragraph 131a)." The outputs of this project combined with the other project currently being carried out by XIFDWG (Quantifying the distribution of unevenly loaded containers carried by roa