Toronto's chief medical officer of health said if the current plans to expand GO service from Union Station to Georgetown go ahead it will have an effect on the health of the people living close to the tracks.

Dr. David McKeown said Monday that 'the expansion would mean about 400 additional diesel train [trips] a day" in the west end, and that will have an impact on the health of people.

"If it goes ahead as currently planned, we would expect to see a worsening of air quality and health impacts in the neighbourhoods adjacent to the line," said McKeown.

In a report prepared for the city's board of health, staff recommended the lines be electrified as soon as possible. Opponents of diesel trains want a stronger recommendation — that the line be electrified right from the start.

Metrolinx spokesperson Jim O'Mara said the regional transit authority will electrify the line, but not for 15 years.

"It's not a cost issue it's a massive re-shaping of the transit network," said O'Mara.

Fifteen years of dealing with diesel trains is not an attractive option for Catherine Kormendy.

"It just seems so backward to me, it just makes sense to start with electric from the beginning," she said.

Her neighbour, Peter Morgan, whose family live 150 metres from the tracks, agrees.

"We have approximately 30,000 kids living along the corridor, 300,000 adults and kids within a kilometre of the tracks. So to say they'll electrify it in 15 years means the health of the people living along the tracks will be sacrificed," said Morgan.

Metrolinx is half way through an environmental assessment and said it will share all its findings with Toronto public health.