Source: imgur.com/a/Xk8K4
 

Right now, cell service when riding the Subway or Scarborough RT is available only when trains are above ground.

At a few random spots, cell service is intermittent, like at ends of TTC station platforms near the entrance or platform ends near above ground tunnel openings.

You will get a strong signal for the few moments riding the train underneath the Luminous Veil above the Don Valley.

Previously, the stretch of track between St Clair and Summerhill stations were completely above ground, but in recent years have been partly covered. Consequently, if your train stops for whatever reason in a few sweet spots, you will have service.

Still on schedule for late this year, 2013, are Cell Service pilot projects at St George and Bloor-Yonge Stations.

Additional Links

• A neat remix of the TTC Subway map I made: the TTC Cell Service Map (imgur.com)

  submitted by colonkay on Reddit Toronto
• Big three mobile carriers stand in the way of company’s plan to bring cellular service to subway - By Matthew Braga, National Post, 16/08/13

• A cellular service map of the Toronto subway - By Derek Flack, BlogTO, September 20 2013