The driver of a school bus hit by a freight train at Carlyle, Sask., last year didn't hear the horn as the train approached and couldn't see it either, the Transportation Safety Board says.

The report released Tuesday concerned a March 26, 2013, bus-train crash that left one child with minor injuries.

As a result of what happened, the TSB said, the provincial government will change its regulations to ensure that in future bus drivers open the side door and driver-side window when they stop at crossings that are not equipped with automatic signal devices.

In the case of the Carlyle crash, the driver, who was 68 and had been driving for 45 years, followed existing provincial regulations and stopped the bus, which had seven children aboard, before trying to cross the tracks.

However, the driver could neither see nor hear the approaching Canadian National Railway train.

The train was going 40 kilometres per hour when it hit the front of the bus.

"The investigation determined that the driver was likely distracted by tasks associated with the road traffic and pedestrian activity in the vicinity of the crossing at the time of the accident," the TSB said in a news release.

In addition, a side mirror and the frame of the bus blocked the driver's view.

That could have been remedied if the driver had been required to open the side window and side door, the TSB says.

It says it has since consulted with provincial authorities to change school bus operating regulations so window and door openings will be required at non-electrified crossings.

The TSB says it expects that change will come into effect in Saskatchewan by the end of this month.