Undesired release of air brakes led to 2019 freight train derailment in the Upper Spiral Tunnel, British Columbia
Richmond, British Columbia, 19 July 2023 — Today, the Transportation Safety Board of Canada (TSB) released its investigation report (R19V0002) into the January 2019 Canadian Pacific Railway Company (CP) freight train derailment in the Upper Spiral Tunnel, near Field, British Columbia (BC).
On the morning of 3 January 2019, a mixed-merchandise freight train, hauling 159 rail cars including 13 carrying dangerous goods, departed Calgary, Alberta, destined for Port Coquitlam, BC. While descending Field Hill, a section of track known for its steep grades and sharp curves, an in-cab alert activated as the front end of the train was exiting the Upper Spiral Tunnel, indicating a train-initiated undesired release of the air brakes (UDR). This occurs when the air pressure in a train’s brake pipe spontaneously increases, causing the automatic release of the air brakes.
In response, the locomotive engineer made a full service brake application, as required by operating rules, and applied the locomotive dynamic brakes to bring the train to a controlled stop. The subsequent rapid deceleration resulted in the block of heavy loaded cars at the tail end of the train running into the empty cars near the centre, leading to the derailment of 15 empty cars in the Upper Spiral Tunnel.
In this occurrence, the train had been assembled using destination marshalling – meaning cars were grouped in blocks destined for the same location – therefore, several heavy loaded cars were placed at the rear end of the train in preparation for the first stop in Golden, BC.
The investigation revealed that, although the train cleared CP’s computer-based train marshalling verification program before departing, it was not compliant with the railway’s General Operating Instructions, which states that heavy cars must be placed as close as possible to the head of the train and light cars should be placed as close as possible to the rear unless the cars behind them are also relatively light.
The investigation also found that the train had experienced an earlier UDR six hours prior to the occurrence, yet a decision to proceed was made without an alternative plan of action. The decision to proceed after the first UDR likely did not take into consideration the risks associated with potential high in-train forces should another UDR occur, especially on the steep descending grade and sharp curves of Field Hill.
Following this occurrence, CP issued a maintenance alert to inspect certain rail cars and make necessary repairs. Additionally, it conducted an extensive review and analysis of mixed-merchandise train make-ups operating west of Calgary and issued an operating bulletin concerning restrictions for handling mid-train empty cars on westward trains.
The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.
For more information, contact:
Transportation Safety Board of Canada