The majority of the Kingston Sub runs close to the northern bank of Lake Ontario and the Saint Lawrence River.

Since 1995, no OCS operation clearance forms need to be filled by train conductors on the Kingston Subdivision.

CTC signals thus provide both permission and authorization for train movements, as is the situation with most main line operation at CN.

In particular, CN mainline freight traffic in the Toronto area no longer follows the Kingston Sub, and is re-directed north of the city along the York Sub.

The section between Pickering Junction and Union Station in downtown Toronto has been sold to Metrolinx for GO Transit service, part of their Lakeshore East line.

Leaving Union station’s rail corridor, the line is intersected by the CN Bala subdivision, before curving slightly north, through the south end of Toronto’s east York community.

From Newcastle, it weaves its way between Lake Ontario and highway 401, to port hope in west Northumberland county.

The 1850s Grand Trunk Railway mainline consisted of 34 stations, many of which have been removed from service or no longer exist.