Ontario NDP Leader Andrea Horwath joined dozens of west Toronto residents who rallied Saturday against the use of diesel locomotives along a new rail link between Pearson International Airport and Union Station.

Residents in areas where the trains will travel are concerned about air pollution and health risks associated with diesel fumes. They are asking the Ontario government to make the 23.3-kilometre rail link electric-powered from the start.

However, Premier Dalton McGuinty has said that the new rail line will start with diesel trains so that it can be ready in time for the 2015 Pan Am Games. The province then plans to switch to electric trains. Construction is expected to begin this spring.

But Horwath said the switch from diesel to electric trains will likely be costly and nearby residents will suffer in the meantime.

"The medical officer of health has said very clearly that this is not good for the health of these citizens and the bottom line is, this train can be electrified from day one," Horwath told CP24 Saturday afternoon at a Clean Trains Coalition gathering.

"If you are going to do something, do it right the first time. Don't do a diesel train now and then at some point down the road electrify it."

The new railway, managed by Metrolinx, will link the Georgetown GO line to the airport. Project-related contracts announced so far total $128.6 million.

A Metrolinx study found that an electrified rail network would save up to $18 million in operating costs each year and between five and 10 minutes over the longest trips.

"We want Dalton McGuinty to listen to our community and to listen to the will of city council, and to build electric trains along this line," local NDP MPP Jonah Schein told CP24.

Schein noted that Torontonians have also been asking for more local stops along the downtown-airport route. Currently, the only planned stops are at Bloor Street and Weston Road.