Calgary Alberta - A communications breakdown led to two CP trains colliding and partly derailing in Calgary's Alyth yard in 2019, a federal investigation concluded.
 
On 9 Mar 2019 a train bound for Medicine Hat was making its way through the rail yard in the city's southeast when it was struck by a remote-controlled train, known as an assignment.
 
The collision of the two eastbound trains led to a total of nine cars and three locomotives derailing in an upright position, while no crew members were injured.
 
That morning, a failure to properly communicate which train would solely occupy a section of track in the yard led to them converging and colliding, states the Transportation Safety Board findings.
 
"The assignment crew members, based on the earlier radio communication, believed that they had granted train 118 permission to occupy the Ogden lead, only up to 50th Avenue, and that the assignment still had exclusive access to the portion of track east of the crossover," concluded the TSB.
 
It noted the Alyth yard lacks the physical barriers found in other rail facilities to prevent such collisions and that clear communication is therefore crucial.
 
"As this occurrence demonstrates, collision or derailment may occur as a result of unclear communications between conflicting train movements, particularly in the absence of physical defences to prevent overlapping authorities," states the report.
 
"It is important that crews follow prescribed verification procedures and repeat back transmissions of safety-critical information to ensure common understanding."
 
That accident occurred about a month after a westbound CP freight train lost control on a steep stretch of track above Field, B.C., and barrelled down the Spiral Tunnels before derailing.
 
Three crew members were killed in that derailment, which was blamed on faulty air brakes.
 
A final TSB report on the tragedy is expected to be released this year.
 
Bill Kaufmann.