Summer swelter could slow subway trains today

Today's high temperatures could slow things down on the TTC, with subway trains forced to reduce their speed in an effort to prevent derailments.
The TTC may at times have to hold trains to a maximum of 40 kilometres an hour in "open cut" sections of the subway today because of the hot weather. (CBC)

Today's high temperatures could slow things down on the TTC, with subway trains forced to reduce their speed in an effort to prevent derailments.

​With forecast highs approaching the 35 C mark today, the TTC may at times have to hold trains to a maximum of 40 kilometres an hour in "open cut" sections of the subway, those stretches of track outside the tunnels.

TTC spokesman Brad Ross said the precaution is needed because steel rails expand in warm temperatures, which affect the alignment of the rails.

"If it expands too much … it could buckle and that could then cause a derailment," he said.

Ross said the speed restriction might add another 10 minutes for some commuters, depending on the trip.

"It does have a domino effect up and down the line," he said.

Ross said the restrictions normally happen around 3 or 4 p.m. in the afternoon.

The high temperatures on trains could pose another challenge for subway riders today.

The TTC is working to repair air conditioning systems on 370 subway cars that run on Line 2.

"We're working very hard to get the air conditioning units back online but it's not going to happen this week unfortunately," said Ross. "It takes about four days [to fix each unit] but we have other maintenance needs that we need to meet."

To help out during rush hour the TTC will operate four of the new Toronto Rocket trains on Line 2. The newer Toronto Rocket trains, which have air conditioning, normally run on Line 1.