3 MARCH 2015
GATINEAU, QUEBEC
The Transportation Safety Board of Canada (TSB) today released
its investigation report (R13W0257) into the derailment of a Canadian National
Railway (CN) freight train at Nickel Lake, Ontario.
On 10 November 2013, at approximately
1727 Central Standard Time, a CN freight train travelling eastward on the
Fort Frances Subdivision derailed 40 loaded grain cars near Nickel Lake,
Ontario. There were two separate groups of derailed cars, 12 cars in one
group and 28 cars in the other. Several of the derailed cars ruptured and
spilled grain. There were no injuries.
The investigation determined that the derailment likely
occurred due to a combination of track and rail conditions and the operation of
long, heavy-loaded unit trains. Each of these factors on its own would probably
not have resulted in the derailment. However, when combined, these factors were
likely sufficient to create the necessary derailment conditions.
Findings
Findings as to causes and contributing factors
- The derailment likely initiated when the high rail of the 4.05° left-hand curve rolled out, allowing the trailing L-4 wheel of the 22nd car (CN 388054) to drop down and ride on the web and base of the high rail, spreading the high rail behind it as it proceeded.
- With the train operating at 37 mph, the curve was under-elevated for this speed, resulting in more lateral forces being exerted on the high rail.
- With the high rail that was reaching its wear limits, 2-point contact at the wheel/rail interface likely occurred, resulting in a lower lateral-to-vertical derailment threshold.
- Heavy loaded unit trains, operating at or slightly over permitted speed, would have accelerated the degradation of the spike fasteners' ability to resist lateral-force gauge widening and rail rollover.
- The high lateral-force rail rollover likely occurred from a combination of train speed on the under-elevated curve, lowered lateral-to-vertical threshold due to 2-point contact on the worn high rail, and degraded rail fastener resistance to dynamic wide gauge.
Findings as to risk
- If rail grinding is not performed following rail cant restoration and gauging, 2-point contact at the wheel/rail interface can occur, resulting in higher lateral forces and increasing the risk of rail rollover.
Other findings
- The delay in braking from the tail end of the train and the fact that the locomotive brakes were not bailed off allowed the braking cars to bunch up, creating a jackknifing situation that increased the severity of the derailment.
- The placement of the distributed power remote locomotive, while not in accordance with Canadian National guidelines, did not contribute to the derailment.
- When evidence from occurrence sites is not preserved, the Transportation Safety Board of Canada may be hindered in determining the causes and contributing factors, and in identifying safety deficiencies in the transportation system.
This report concludes the Transportation Safety Board’s
investigation into this occurrence. The Board authorized the release of this
report on 28 January 2015. It was officially released on 03 March 2015.