The modern 510 Spadina route began as the 604 Harbourfront LRT route along Queens Quay in 1990, using CLRV and ALRV streetcars. The route was later renamed the 510 Harbourfront. It became the 510 Spadina and replaced the 77 Spadina bus when a new dedicated right-of-way was opened in 1997. The right-of-way extended the track north along Spadina Avenue from Queens Quay to Spadina station on the Bloor subway line. The term "light-rail transit", which had been adopted to project an image of modernity, was dropped when it led to residents and newspaper reporters imagining elevated guideways like those of the Scarborough RT running through their streets. It was found that the project was much easier to sell to the public and politicians when it was described as an improvement to the speed and reliability of traditional streetcar service. In 2000, when the Queens Quay streetcar tracks were extended west to Bathurst and Fleet Streets, the name Harbourfront reappeared for a 509 Harbourfront route between Union and Exhibition Loop. The 509 and 510 routes share the trackage that had been used by the 604. In 2005, The Globe and Mail newspaper published an article that criticized the switch to a dedicated right-of-way streetcar as being less beneficial than promised. Based on TTC documents, the author argued that service is about one minute slower during afternoon rush hour than in 1990. The author also cited TTC documents which show that the cost-to-revenue ratio of the route has fallen with the switch from buses to streetcars. Mitch Stambler, the TTC's manager of service planning, responded by pointing out that streetcars offer a smoother and quieter ride, zero emissions, and economic development. Ridership increased from 26,000 per day on the 77 bus route to 35,000 per day on the Spadina streetcar in 2004 and to over 45,000 per day in 2005–2006. Streetcars on the Spadina portion run every 2–3 minutes every day. On December 15, 2008, the next vehicle arrival notification system was installed for the 510 streetcar in the Spadina and Union subway stations. The next vehicle arrival notification system includes a display screen that shows the location of the streetcars in "real" time with a delay of one minute. On June 18, 2012, all streetcar service on the line was suspended and replaced by buses. This was to allow major track work to be completed in preparation for the TTC's new low-floorBombardier Transportationcustom-made Flexity Outlook streetcars which were scheduled to enter service on the Spadina line in 2014. The upgrades were completed and full streetcar service was restored two years later on August 31, 2014, including a ceremony at 10:00 am when the first two accessible low-floor Flexity vehicles officially entered revenue service. On September 6, 2015, after a 13-year absence, the TTC reinstated its overnight service on this route. The night service was designated first as 317 Spadina before being renumbered 310 Spadina on September 3, 2017, and was part of the expanded Blue Night Network streetcar services resulting from a $95 million investment from Toronto City Council. During overnight periods, streetcars operate approximately every 30 minutes. The TTC had operated an overnight service using buses on Spadina from 1987 until 1992 when it was discontinued due to a series of cutbacks in TTC service. On May 14, 2018, 510 Spadina became the second streetcar route in Toronto to use a pantograph instead of the trolley pole for electrical pickup.
Route
510 streetcars operate entirely within dedicated streetcar Rights-of-Way, along Spadina Avenue, Queens Quay Boulevard and in a tunnel under Bay Street. Most stops along the routes are surface stops with islands separating the regular traffic from the streetcar tracks, and have streetcar traffic signals, partial shelters, and railings to protect patrons from the traffic. Streetcars serve Union and Spadina subway stations from underground streetcar stations, and an additional underground streetcar station exists at Queens Quay on the approach to Union Station. The route consists of three branches, which vary only by the extent of the line they cover. Throughout most of the day, streetcars alternate between branch 510A which covers the entire route, and branch 510B, which operates only from Spadina Station to Queens Quay Boulevard. A small number of trips also operate on branch 510C between Spadina Station and King Street.
510A Spadina: Spadina station to Union station via Queens Quay
510C Spadina: Spadina station to Spadina Ave and King St.
Route 310 Spadina runs overnight between Spadina and Union stations, replacing the 510 Spadina service. It is part of the TTC's Blue Night Network, operating from approximately 1am to 5am.
