The TTC: The Sweatier Way.

Commuters are facing sweltering rides as the transit agency works to replace old, worn-out air-conditioners.

But how hot is it exactly?

Using a thermometer, the Star measured temperatures of up to 32.5 C on a Line 2 train car as it travelled between Sherbourne and Dundas West Stations Wednesday – 3.5 C hotter than the temperature at both platforms and 1.5 C higher than the temperature outdoors during the same time frame.

Another car on a different train travelling from Broadview to Donlands hit 29.5 C. An air-conditioned car in the same train was 25 C.

And as Torontonians braved a record-breaking high of 35C outside Wednesday, a Star reporter went underground, riding several Line 2 trains Wednesday afternoon, starting at Yonge Station.

The thermometer registered a temperature of 28 C after five minutes on the platform.

The temperature gradually dropped after boarding the first car on an eastbound train, reaching 24 C three stations later at Broadview.

Switching into the non-air-conditioned second car of the same train, the temperature immediately rose, hitting 29.5 C three stations later at Donlands.

The platform-level temperature at Donlands Station after five minutes was 27.5 C.

Heading back west to Sherbourne Station, an air-conditioned car measured 25 C.

The temperature at Sherbourne Station after 10 minutes was 29.5 C.

Boarding the third car of a westbound train which was not air-conditioned, the temperature hit 31.5 C three stations later at St. George, 32 C one station later at Spadina, and, finally, 32.5 C two stations later at Christie. It remained at 32.5 C for the remainder of the journey to Dundas West Station.

The temperature outside at that time was 31 C.

For those who can’t take the heat, TTC spokesperson Susan Sperling suggested stepping out and waiting for the next train, or transferring into a different car – the first and last cars of every train are guaranteed to have working air-conditioning because that’s where the train’s two operators work.

“Operators don’t have the option of getting off and waiting for another train, and they’re in there for several hours a day,” Sperling said, noting it was a “health and safety issue.”

Toronto Paramedics spokesperson Kim McKinnon said the temperatures on trains haven’t resulted in increased medical calls, but encouraged anyone who travels on Line 2 to bring water and recognize the symptoms of heat-related illness, which include dizziness, light-headedness and suddenly not sweating anymore.

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The new air-conditioning units, which Sperling said have a “very good success rate,” should be installed on all cars by next summer.

Although most of the work has been done, 20 to 25 per cent of the TTC’s 370 older-model train cars are still awaiting replacement air-conditioner units, explained Sperling.

“[The current units] are old and when they get over-stressed, like on very hot days and in crowded conditions, they have to work harder – they can fail,” she said, adding that the replacement is taking time due to the sheer number of cars the TTC has to look at.