The trail runs south from York Mills Road, east of and roughly parallel to Leslie Street.

[5] Most of the trail runs between residential areas while the southern portion is bordered by industrial and commercial properties, following the roadbed of a former railway line.

[6][7] At the north end, just south of the bridge at York Mills Road, the trail runs parallel to the still-active tracks of the Canadian National Railway (CNR) Bala Division.

(Oriole is at York Mills Road, and Donlands is about 450 metres north of Eglinton Avenue East.)

The Canadian Northern Railway (CNoR) built the line originally to access the CPR North Toronto Station.

The complex replaced an engine house in the Don Valley at Rosedale that had limited capacity and was vulnerable to flooding.

[10][12] The locomotive shop survives today, and is occupied by Longo's Leaside supermarket on Laird Drive.

The CNR once had running rights to switch industries on the north side of the CPR midtown line all the way to the TTC's Hillcrest Complex at Bathurst Street.

[11] In April 2009, the Province of Ontario purchased the Don Branch (running between downtown Toronto and Leaside).

Six 2-foot-thick (0.61 m) beams span the 15-foot-wide (4.6 m) opening, spaced to handle the weight of locomotives and heavily loaded railcars.