Implementation of the full 10 and 20-min. service levels on the Combined CN/CP route requires a new mainline track
6 on the Don Branch of the CP Belleville Subdivision from near downtown to the point where it joins the major CP line just west of Millwood Road in Leaside. Two new mainline tracks for co mmuter service are re quired from there through the Leaside industrial area, to a point just north of Eglinton Avenue where they would join the CN Leaside Branch by a proposed rail/rail grade separation at "Donlands". One new mainline track is required on the CN Leaside Branch through Don Mills, and on to Richmond Hill via the CN Bala Subdivision. The upgrading for full service would provide for railway operations fully grade-separated from all other forms of traffic over the entire route
7, and its construction would have long term environmental impacts which are thought to be acceptable. New or relocated stations can feasibly be established on the route at several major cross streets, so as to connect with bus routes operating in all commuter rail ridership "catchment" areas of interest; also, it is thought marginally feasible to include an inter-connection at the Bloor-Danforth subway should ridership forecasts justify that station.
6 A long and expensive ($13 million) new viaduct to carry the second mainline track over the Bayview Avenue Extension, the CN Rail Bala Subdivision and the Don River near the “Brickworks" in the Don Valley is required only forthe full 10-min. service level
7 Excepting a minimal number of private level crossings and the public one at Langstaff Road north of Thornhill.
Use of this shorter (by 2 miles) route through Don Mills and Leaside would reduce trip time between Highway 401 and Union Station by 6 to 8 minutes, a 25% to 35% reduction as compared to continued use of the present all-CN Bala Subdivision route. However, there is a potential problem in the Leaside industrial area where the property required for the proposed Leslie Street Extension overlaps that necessary for implementation of this Combined CN/CP commuter rail route; studies need to be undertaken with a view to defining how these two proposals may be made compatible with one another.