Runaway Canadian Pacific train rolls 230 metres through Calgary

File: A Canadian Pacific Railway employee walks along the side of a locomotive in a marshalling yard in Calgary, Wednesday, May 16, 2012. Jeff McIntosh / The Canadian Press

The Transportation Safety Board is investigating after 80 uncontrolled rail cars rolled a quarter kilometre along a track at one of Canadian Pacific Railway’s main marshaling yards in Canada.

The incident happened Tuesday at 3 p.m. at Alyth yard in southeast Calgary.

TSB said the movement of the train — weighing over 9,500 tonnes — didn’t cause any derailments or injuries. Most of the freight cars were loaded when the train rolled away, but there were no dangerous or explosive goods on board.

It’s unclear what caused the incident.

In July of 2013, 47 people were killed when a runaway train derailed and exploded in downtown Lac-Mégantic, Que..

A TSB investigation later concluded 18 factors led to the disaster, including poor training, mechanical problems and sloppy safety oversight.

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READ MORE: Lax safety measures, poor training led to fatal Lac-Mégantic rail disaster

WATCH: TSB release animation recreating Lac-Megantic train derailment

In June, the TSB called on Transport Canada to modernize training and qualification rules for railway employees after another runaway train incident in 2016 near Toronto.

In that case, the board found automatic brakes had not been engaged by two employees assembling a train which contained flammable liquid.

READ MORE: TSB calls for update to railway employee training, qualification rules after runaway train incident near Toronto