Editing Line 1 Yonge–University (section)

=== Gap trains ===
Gap trains are empty trains stored on [[pocket track]]s and brought into service in a gap between full-route trains to relieve overcrowding.<ref name="TheStar-2018-11-07">{{cite news |url=https://www.thestar.com/news/gta/2018/11/07/ttc-using-gap-trains-to-improve-service-on-busiest-subway-line.html |title=TTC using 'gap trains' to improve service on busiest subway line |newspaper=[[Toronto Star]] |first=Ben |last=Spurr |date=November 7, 2018 |access-date=November 8, 2018 |archive-date=November 8, 2018 |archive-url=https://web.archive.org/web/20181108175225/https://www.thestar.com/news/gta/2018/11/07/ttc-using-gap-trains-to-improve-service-on-busiest-subway-line.html |url-status=live }}</ref> In October 2018, the TTC restarted the practice of using gap trains to relieve crowding at {{stl|TTC|Bloor–Yonge}} and {{stl|TTC|St. George}} stations, where respectively 225,000 and 135,000 passengers transfer trains daily. The TTC observed that one empty gap train can clear a crowded platform at Bloor–Yonge.<ref name="TheStar-2018-11-07" />

The TTC had previously run gap trains prior to late 2017 but had discontinued the practice because of a "change in operating philosophy". The practice was reinstated in response to a potentially dangerous overcrowding incident that occurred at Bloor–Yonge in January 2018.<ref name="TheStar-2018-11-07" />

In October 2018, the TTC used three gap trains, which sat on pocket tracks near {{stl|TTC|Davisville}}, {{stl|TTC|Eglinton}} and {{stl|TTC|York Mills}} stations and moved into southbound service when station over-crowding was detected. For November 2018, the TTC planned to run a fourth gap train (which would sit on either the pocket track between {{stl|TTC|Lawrence West}} and Glencairn stations or the pocket track between Eglinton West and St. Clair West stations) in the morning peak period plus another during the afternoon peak.<ref name="TheStar-2018-11-07" />

Gap trains can also increase the capacity of Line 1, which often runs above its scheduled capacity of 28,000 passengers per hour. To address that demand, the TTC normally runs an average of 25.5 trains per hour through Bloor–Yonge and St. George stations in the morning peak period. With three gap trains, it can run up to 28 trains per hour.<ref name="TheStar-2018-11-07" />