GO Transit operates an urban rail network, commonly referred to as the GO train, throughout the Greater Toronto and Hamilton Area (GTHA) and the Greater Golden Horseshoe region of Ontario. Described as both a commuter rail and regional rail system, it comprises seven lines and 71 stations, converging at Union Station in Toronto. In , the system had a ridership of passengers per year.

GO Transit started on May 23, 1967, running single-deck trains powered by diesel locomotives in push-pull configuration on a single rail line along Lake Ontario's shoreline.Garcia et al.: Lakeshore corridor When GO trains began operation, they ran on tracks mostly owned by the two major freight railways of Canada: Canadian National and Canadian Pacific. Over time, GO Transit (and subsequently Metrolinx) have acquired tracks, ensuring GO Transit has control over track maintenance and expansion. Metrolinx currently owns 80% of the GO's rail corridors.

All GO Transit fares are calculated by the fare zones that the origin and destination of the trip are in, as well as by passenger category (adult, student, senior or child). GO train fares are not differentiated based whether or not buses are used for part of the trip. The GO Transit rail fleet consists of 90 MPI MP40 locomotives and 979 Bombardier BiLevel Coaches.

Lines and stations

+ GO Transit rail linesLineIDCities servedTerminiService (from Union Station)Route variantsLakeshore WestLWToronto Mississauga, Oakville, Burlington, Hamilton, St. Catharines, Niagara FallsUnion Station Aldershot GO, Hamilton GO, West Harbour GO, Niagara Falls stationTwo-way all day service to West Harbour Limited two-way service to NiagaraExpressLakeshore EastLEToronto Pickering, Ajax, Whitby, OshawaUnion Station Oshawa GOTwo-way all day serviceMiltonMIToronto Mississauga, MiltonUnion Station Milton GORush hour one-way from Milton in morning Rush hour one-way to Milton in afternoon No weekend service No service outside rush hourKitchenerKIToronto Brampton, Georgetown, Acton, Guelph, Kitchener, StratfordUnion Station Bramalea GO, Mount Pleasant GO, Kitchener GO, Stratford stationTwo-way all day service to Bramalea Limited two-way service to Kitchener Two-way all day service to Mount Pleasant on weekends One daily round trip to StratfordExpressBarrieBRToronto Vaughan, King City, Aurora, Newmarket, Bradford, BarrieUnion Station Aurora GO, Bradford GO,Allandale Waterfront GORush hour one-way from Barrie in morning Rush hour one-way to Barrie in afternoon Two-way service to Aurora outside rush hour Limited service to Barrie outside rush hour Two-way all-day service to Aurora on weekends Limited service to Barrie on weekendsRichmond HillRHToronto Richmond HillUnion Station Bloomington GORush hour one-way from Bloomington in morning Rush hour one-way to Bloomington in afternoon No weekend service No service outside rush hourStouffvilleSTToronto Markham, Whitchurch-StouffvilleUnion Station Unionville GO,Mount Joy GO, Old Elm GORush hour one-way service from Old Elm in morning Rush hour one-way service to Old Elm in afternoon Two-way all day service to Mount Joy outside rush hour Two-way all day service to Mount Joy during weekends Limited service to Old Elm during weekends

History GO Transit rail service began on May 23, 1967, on a single rail line along Lake Ontario's shoreline. GO train service ran throughout the day from Oakville to Pickering with limited rush hour train service to Hamilton. This line, now divided as the Lakeshore East and Lakeshore West lines is the keystone corridor of GO Transit, and continued to be its only rail line for its first seven years of operation. GO's other five lines were opened between 1974 and 1982, significantly expanding the rail network from 86 to 332 kilometres long, and from 16 to 43 stations.

To that point, all of GO's rail services ran on tracks mostly owned by the two major freight railways of Canada: Canadian National (CN) and Canadian Pacific (CP). in 1988, a small but significant milestone in network growth occurred when it expanded its Lakeshore East line on new track it built by itself. But following that, the network experienced two long-distance extensions to southern Barrie and in 1990, only to have those extensions reversed three years later. GO did extend its Lakeshore East line again in 1995 from to , finishing that line as it exists today.

The reach of GO's network remained relatively unchanged between 1996 and 2005. However, seven new infill stations were opened along the Bradford and Stouffville lines. This coincided with GO's initial purchases of the rail corridors it operated on, taking ownership of the entire Stouffville line past Scarborough station, and most of the Barrie line north of the Toronto border. In addition, GO took control of the critical Union Station Rail Corridor, which all GO trains on all lines used. By the end of 2005, GO owned over a third of its rail network.

From 2007 to 2017, GO's network saw six extensions, requiring the Bradford line to be renamed as the "Barrie line", and the Georgetown line to "Kitchener line." These long-distance extensions, along with the other extensions on the Lakeshore West, Richmond Hill and Stouffville lines, expanded GO's network length by 29%. Six critical corridor purchases were also made, tripling its length of owned corridors and bringing its ownership percentage to over 80%. Finally, 10 new stations were added, one of which coincided with the opening of the Toronto–York Spadina subway extension, creating a new interchange between GO and the TTC subway.

In 2019, Lakeshore West service was extended from Hamilton to . This was the first major expansion of the GO network since service to Kitchener began in 2011. In 2021, a two-year pilot project extended the Kitchener line to London however this did not continue past 2023. In November 2025, the 70th GO station opened at , which created another transfer to the Toronto subway.

Future extensions

Lakeshore East to Bowmanville

A 20km extension of the Lakeshore East line to Bowmanville was announced by then-premier Kathleen Wynne in 2016. Construction began on July 22, 2024 and is not expected to finish for years. No completion date has been provided. The extension is expected to cost $730 million, and will provide two-way all day service. The line will travel upwards from the current Oshawa GO station and continue along the CPKC corridor to Bowmanville, adding four more stations, Thornton's Corners East, Ritson, Courtice, and Bowmanville.

Stouffville to Uxbridge Rail beyond Stouffville to Uxbridge was previously owned by the York–Durham Heritage Railway (YDHR). After the YDHR went bankrupt in January 2024, Uxbridge considered extending rail operations. Uxbridge decided in December 2024 that the liability and obligations were not worth the cost, and decided to reject a Stouffville extension to Uxbridge.

Future improvements

Two-way all day service on the Milton line The Milton line corridor is owned and operated by Canadian Pacific Kansas City which has restricted the number of passenger trains, only allowing for one-way service. In 2024, the Ontario government under Doug Ford called on the federal government to share the cost of construction for two-way all day service on the Milton line. The project would involve a complete separation from CPKC's tracks by building dedicated GO Transit tracks along the rail corridor, and is estimated to be at $6 billion dollars. No timeline has been provided, construction has not yet started, and seems to have been supplanted by the "GO 2.0" project to build the Missing Link.

A long-proposed solution to allow access for passenger trains on the Midtown line is a re-routing of CPKC freight traffic known as the "Missing Link". The Missing Link would extend the Halton subdivision along Highway 407 and link back up with the Midtown corridor between Lisgar GO Station and Milton GO Station. This would free up the Midtown corridor and the Milton line for passenger rail. In 2015, Mississauga attempted a feasibility study for the Missing Link, but did not go forward with constructing it. The Missing Link is considered an ambitious project, requiring negotiations to make CPKC and CN share the Halton and York subdivision (both of which are currently owned by CN). In 2024, the Progressive Conservative Party announced plans to build the Missing Link to free up both the Milton and Kitchener line.

GO train electrification In 2010, then-premier Kathleen Wynne announced plans to electrify GO Transit. Electrification would drastically cut down on GO Transit's carbon emissions and would allow GO Transit to run faster, more frequent trains, increasing ridership. In 2018, it was decided to use an overhead wire system over a third rail. Hydrogen fuel cells were studied as an alternative to rail electrification but ultimately were deemed unfeasible. A report suggested the trains would be 30% faster and 60% cheaper per kilometre. In 2022, the Ontario government under premier Doug Ford began the first phase of electrification, with plans to electrify 600 kilometres of track and an estimated finish date of 2032.

Track works

Single tracked segments on the GO network prevent increases in rail service. Metrolinx is currently constructing a second track on the Stouffville line between Kennedy GO and Unionville GO.

The Kitchener line has no current plans to double track further beyond Mount Pleasant GO, however Metrolinx is constructing strategic passing siding to improve capacity. Metrolinx has plans to expand the passing siding near Breslau, add a passing siding at Guelph GO, and a passing siding at Acton GO.

The Barrie line is mostly single tracked and construction is currently underway to add a second set of tracks up to Aurora GO.

Future lines Bolton line

GO Transit rail service to Bolton was first proposed by the Ontario government under the MoveOntario 2020 plan in June 2007. It was subsequently carried over to The Big Move, where it was placed on the 15-year plan. In November 2010, Metrolinx completed a feasibility study that focused on utilization of Canadian Pacific Railway's Mactier subdivision, which runs from the West Toronto Diamond in Toronto northward to Bolton. Four different service alternatives were assessed to determine the best method to carry passengers into Toronto from the Mactier subdivision, and the preferred option was to direct trains east-west along CN's Halton subdivision, and north-south again along GO Transit's existing Barrie line. This would provide four new stations in the communities of Woodbridge and Kleinburg in the City of Vaughan, and Bolton in the Town of Caledon, and also use the existing Downsview Park station before terminating at Union.

The feasibility study estimated that minimum infrastructure costs were $160 million for peak direction rush-hour service, and resulting ridership was forecasted to be 2,391, 2,884, and 4,388 in 2015, 2021, and 2031, respectively, in the morning peak period. If service was increased for two-way all-day service, total costs increased to $210 million, and ridership was forecasted to be 6,074, 7,324, and 11,146 in 2015, 2021, and 2031, respectively. Metrolinx determined that the projected ridership did not justify the costs, and downgraded the Bolton line from the 15- to the 25-year plan on February 14, 2013, when amendments were made to The Big Move.

In 2025, as part of a campaign promise, the Progressive Conservative Party under Doug Ford announced plans to create the Bolton line.

Midtown corridor and Peterborough line

The Midtown corridor refers to three new GO Transit services in The Big Move. The first is a Crosstown line from Dundas Street to the former CP North Toronto and Leaside stations in Toronto. The second and third segments would extend east from North Toronto and/or : the Seaton line to Seaton, and the Locust Hill line to Locust Hill.Metrolinx, Schedules 1 & 2