Toronto-gauge railways

Toronto-gauge railways are tram and rapid transit lines built to Toronto gauge, a broad gauge of 4 ft 10+7⁄8 in (1,495 mm). This is 2+3⁄8 in (60 mm) wider than standard gauge of 4 ft 8+1⁄2 in (1,435 mm) which is by far the most common track gauge in Canada. The gauge is unique to the Greater Toronto Area and is currently used on the Toronto streetcar system and the Toronto subway (three heavy-rail lines), both operated by the Toronto Transit Commission. Several now-defunct interurban rail systems (called radial railways in southern Ontario) also once used this gauge. The Halton County Radial Railway, a transport museum is located on one of the former interurban lines and uses the Toronto gauge.

The unique gauge has remained to this day because it is easier to adapt new rail vehicles to fit the gauge than to convert the entire system to standard gauge. An alternate name for Toronto gauge is TTC gauge, named after the Toronto Transit Commission, the only operator currently using the gauge although the gauge existed prior to the creation of the TTC in 1921.

All TTC streetcar routes, both past and present, have used the Toronto gauge. The TTC had three predecessor companies that also used Toronto gauge, each with a network of streetcar lines within the City of Toronto:

The Toronto Street Railway created the Toronto streetcar system opening its first horsecar line in 1861. It also created the broad Toronto gauge to allow horse-drawn wagons and carriages to use the inside of the rail for a smoother ride through muddy, unpaved streets. The gauge also had the effect of precluding the movement of standard-gauge freight cars along streetcar lines. When its franchise ended in 1891, the Toronto Railway Company (TRC) took over the system and replaced horse-drawn streetcars with electric trams; it continued the use of Toronto gauge. Because the TRC refused to service neighbouring areas annexed by the City of Toronto, the City created the Toronto Civic Railways (TCR) in 1911 to serve those areas. TCR lines, clustered in the west end, east end and mid-town, were not interconnected. To move streetcars between carhouses, the TCR used the tracks of the TRC, which is one reason that the City chose Toronto gauge for the TCR. The other reason is that when the TRC franchise ended in 1921, the City wanted to merge the two systems. There were no permanent links between the tracks of the TCR and TRC; temporary track was laid at night when the TCR needed to transfer streetcars. When the TRC franchise ended in 1921, the TTC acquired both the TRC and the TCR and amalgamated the two systems, permanently linking their tracks.

Toronto gauge was first used for the horsecar system opened by the Toronto Street Railway in 1861. Two explanations are offered for the width of the gauge:

According to the TTC, advocating the first explanation, the City of Toronto feared that the street railway franchise operator would allow the operation of steam locomotives and freight trains through city streets, as was common practice in Hamilton, Ontario (until the 1950s) and in many US cities, such as New York City and Syracuse, New York.

However, fear of freight trains invading the streets was from the era of about 1891 to 1921, over 30 years after the creation of Toronto gauge, which makes it an unlikely reason for the Toronto gauge. During this era, railway entrepreneurs William Mackenzie and Donald Mann controlled the Canadian Northern Railway, the Toronto Railway Company plus several radial railway lines including the Toronto Suburban Railway. About 1912, the Toronto Suburban wanted to convert its system from Toronto gauge to standard gauge, but the City of Toronto obtained a court injunction blocking the re-gauging over fears of freight cars in the streets. The railway, however, prevailed and the system was converted to standard gauge in 1917.

Also, horsecar tracks could be of very light construction, adequate for horse-drawn trams, but unsuitable for heavier vehicles. When the Metropolitan Street Railway converted its streetcar line in North Toronto from horse to electric operation, the faster heavier electric trams damaged the horsecar rails, which required the line to be shut down and the track rebuilt to a higher standard.