The Toronto Transit Commission (TTC) maintains three rapid transit lines and 75 stations on 76.9 km (47.8 mi) of route.[1] There are also two light-rail lines under construction.
Tunnels are either square or round, depending on the method of their construction: Square tunnels were built with the cut and cover method of digging trenches down from the surface, constructing the tunnel structure, and then backfilling.[2] Round tunnels are bored using a tunnel boring machine (TBM). The cut and cover technique was used extensively on the oldest portions of the subway system, while newer sections were predominantly or, in the case of the Toronto-York Spadina Subway Extension (TYSSE), which opened in 2017, entirely bored.
Some sections of track run on the surface, the most notable on the heavy rail subway system being the stretch of Line 1 Yonge–University in the median of Allen Road. However, the former light metro Line 3 was a surface or elevated route for nearly its entire length.
Crossovers
The crossover at Vaughan Metropolitan Centre station with a departing train crossing between the northbound platform and the southbound trackSurface crossover at Wilson station
Diamond crossovers (or "scissors crossovers") are X-shaped track assemblies that are used on the heavy-rail subway lines, particularly at terminal stations, to allow trains to switch to the opposite platform or track to reverse direction. They also exist at some through stations (mostly those that were former terminal stations) where they are often used to short turn trains. A single crossover just east of Union Station is what remains of the former diamond crossover, which was used when the station marked the southern terminus of the original line.
The light-rail lines (Line 5 Eglinton and Line 6 Finch West) in some locations use a pair of single crossovers (one facing-point and the other trailing-point) or sometimes just a single crossover (either facing-point or other trailing-point) instead of diamond crossovers.
Crossovers are found in the vicinity of the following stations. Unless otherwise described, they are diamond crossings.
East of Humber College (terminal station; pair of single crossovers)[10]
Between Westmore and Martin Grove stops (pair of single crossovers)[11]
East of Albion stop (trailing-point crossover)[11]
East of Mount Olive stop (pair of single crossovers)[12]
East of Milvan Rumike stop (pair of single crossovers)[13]
East of Norfinch Oakdale stop (pair of single crossovers)[13][14]
East of Sentinel stop (pair of single crossovers)[14]
West of Finch West (terminal station; double crossover)[15]
Centre and pocket tracks
The centre storage track (visible at left) north of Finch West station. Note the cut-away side of the bored mainline tunnel to accommodate the centre track, which was constructed after the initial boring work.
Centre tracks allow a train to enter from either end into a third track, longer than the length of a standard train, between the two service tracks. Trains can either layover or short turn there, allowing other trains to pass them by, or reverse direction from this position with minimal interference with through trains compared to crossovers, which requires the reversal to take place on station platforms. Sometimes, in-service trains are diverted into centre tracks when there is track maintenance on one of the service tracks. Pocket tracks are a variation on the centre track, accessible only from one end. Some storage tracks have a short stub extending beyond the convergence back to the service tracks used to store work cars. All operating centre-track structures (with the exception of Finch West station, which was partially bored and has three fully separate tunnels) were built using the cut-and-cover method, and there are support columns between the tracks. However, at the under-construction Avenue and Laird stations on Line 5 Eglinton, which were "mined" rather than excavated via cut-and-cover, all three tracks are housed within single tubular, columnless tunnels.[16]
Storage tracks are found in the vicinity of the following stations:
The west (southbound side) tail track at Vaughan Metropolitan Centre station. Note the trackless tunnel section for a potential third tail track at right.The unusually short tail track at Don Mills station
On the heavy rail lines (1, 2 and 4), tracks usually continue for roughly the length of a train beyond the last station on a line; these are known as tail tracks. The only exception to this is at Don Mills station, where the tail tracks are less than two cars in length. This is likely because storage capacity is available at Sheppard–Yonge, which can store enough trains to service the line. The tail track structures at some terminal or former terminal stations also have, or have provisions for, a third tail track. Finch station has such a triple configuration, Vaughan Metropolitan Centre station is a terminal station with a trackless tunnel section for installation of a potential third tail track, and Sheppard West station was a former terminal also built with a trackless third tunnel north of it, which could now accommodate a future standard pocket track.[4]
Other track features that exist include the following:
The Bloor wye was used for interlining between Lines 1 and 2 in 1966:
North of Museum station, the tracks split, with the Line 1 mainline leading west to St. George station (upper), and the other east to Bay lower (abandoned a few months later in late 1966).
The eastbound track from Bay lower joins the Bloor–Danforth line just before Yonge station while the westbound track from Bay lower turns and meets the southbound track just north of Museum station.
The eastbound tracks approaching St. George station from Spadina on the Bloor-Danforth line split, with one heading for St. George lower and the other heading for St. George upper.
The westbound track headed to Spadina station west of St. George upper now includes a switch that allows trains to run to Spadina station on the Bloor line, which was built more than a decade after the interlining trial was completed.
An access track leading west to Wilson Yard south of Sheppard West station from the southbound direction, defaulting from the crossover track section leading to/from the station's northbound platform. Trains needing to access the yard from the south must reverse at the station (from either side of the island platform) or access it from the crossover north of Wilson station.
A maintenance track, accessible from the eastbound track on the Bloor–Danforth line, just west of Warden station. Trains must run in reverse to access this siding
On Line 5, immediately east of Mount Dennis station, there is a wye junction to connect the line to its maintenance and storage facility.[8]: 4:34
On Line 6, at York Gate Boulevard, there is a wye junction to connect the line to its maintenance and storage facility. Most of this wye is in a street intersection partially in mixed traffic.[14]
The Sheppard Wye allows the movement of out-of-service trains between the Sheppard line and the Davisville Yard on the Yonge line. The wye has the following features:
Northbound Yonge line to eastbound Sheppard line: track switch on the Yonge Line that meets the Sheppard line east of Sheppard–Yonge station
Westbound Sheppard line to southbound Yonge line: west of Sheppard–Yonge station on the Sheppard line storage tracks and switches allow trains to proceed from east to south connecting with the southbound Yonge line just south of Sheppard–Yonge station
Each subway yard has different features that join them to the mainline. Subway operators generally get their train at a point where the yard meets the main line, at the Greenwood Portal, the Davisville Buildup (third platform of Davisville station), or the Wilson Hostler (platform-like in appearance seen heading between Wilson and Sheppard West stations on the east side of the yard) depending on the home yard. The light-rail lines have a similar feature at their maintenance and storage facilities.
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