On 27 March 2016, at about 0235 Central Standard Time, an empty freight car separated from a train during remote control locomotive system switching operations at Canadian Pacific's Sutherland Yard in Saskatoon, Saskatchewan. Rolling uncontrolled, the car entered the main track, travelled about a mile, including through two public railway crossings, before coming to a stop. Both crossings were equipped with automated grade crossing warning systems. There were no injuries and no derailment.
The investigation determined that while switching without air, the recently qualified crew had disengaged the coupling on the last car in order to leave it in the track. Before it was completed, the operation was interrupted when another freight train requested permission to enter the yard with its locomotives. To allow the locomotives to pass, the crew decided to reverse its entire train into the track, forgetting that the coupling on the last car had been disengaged. When coming to a stop after backing up, the last car separated from the movement. Because the air brakes were not connected and there was no derail in place, the car continued to roll uncontrolled through the yard, entering the main track.
As a result of the TSB investigation into the 2013 Lac-Mégantic accident, the Board recommended that Transport Canada require Canadian railways to put in place additional physical defences to prevent runaway equipment (R14-04). Although not all uncontrolled movements have such major consequences, in this occurrence, the car entered the main track unimpeded and rolled uncontrolled over two public crossings before their warning systems fully deployed.
Uncontrolled movements are low frequency–high-risk events that can occur due to loss of control, switching without air, or insufficient securement. Uncontrolled movements that affect the main track will typically present the greatest risk of adverse outcomes, particularly if dangerous goods are involved.
In Canada, over the past 10 years, there were 541 occurrences involving uncontrolled movements, 32% (175) of which were directly related to switching without air brakes. Of the total uncontrolled movements, 56% resulted in a collision and 11% affected the main track, with many of these occurrences creating a risk to the public or a risk of collision with another train. The most recent five-year average (59.8) of uncontrolled movements is about 10% higher than the ten-year average (54.1).
Following this occurrence, the rail company resumed the use of air brakes and the use of conventional (three-person) crews during switching operations at Sutherland Yard.