TSB investigation determines the derailment caused by excessive truck hunting on the empty centre beam bulkhead flat car.
RICHMOND HILL — The Transportation Safety Board of Canada (TSB) says worn components on a rail car led to the derailment and collission between a Canadian National (CN) freight train and VIA Rail passenger train in August 2014 near Gananoque, Ont.
While there were no injuries, rail cars on both trains were damaged. The fuel tank on the VIA locomotive was punctured, releasing about 1000 litres of diesel fuel. The last six cars on the CN train derailed.
The TSB investigation determined the derailment was caused by excessive truck hunting on the empty centre beam bulkhead flat car. Truck hunting is the side-to-side movement of wheel sets within a freight car truck.
Under certain conditions, truck hunting can become excessive and leads to wheel lift or wheel climb, either of which can cause a derailment.
In this case, the excessive truck hunting was influenced by the type of car, the speed of the train, the worn condition of the constant contact side bearings (CCSB) and the friction wedge, as well as by the truck type. When inspectors visually inspect these rail cars, they look for contact between the CCSB and the car body underframe. However, the investigation determined that visual inspections alone may not have been enough.
The board is concerned that current detector systems and visual inspection programs may not identify cars susceptible to truck hunting prior to them encountering conditions known to initiate excessive truck hunting, increasing the risk of derailments.
Following the occurrence, both CN and Canadian Pacific reintroduced speed restrictions for all empty centre beam bulkhead flat cars. CN also undertook a program to upgrade the CCSBs on two series of centre beam flat cars.