The T series, also known as the T1, is the fourth series of rapid transit rolling stock used in the subway system of Toronto, Ontario, Canada. They were ordered by the Toronto Transit Commission (TTC) in 1992 and built in one production set between 1995 and 2001 by Bombardier Transportation in Thunder Bay, Ontario, Canada. Currently based entirely out of Greenwood Subway Yard, the T1s are the older of the two currently active series of rolling stock on the heavy-rail lines in the Toronto subway network. Following the introduction of the newer Toronto Rocket train sets, all T1 trains now operate exclusively in six-car configurations on Line 2 Bloor–Danforth. They previously operated on Line 1 Yonge–University and in a four-car configuration on Line 4 Sheppard until the retirement of the last remaining H-series trains in 2014 and until the implementation of one-person train operation on the latter in 2016. Design advances The T1 cars entered service between 1995 and 2001 and became the mainstay of the TTC subway fleet. By 1999, they had replaced the older M1s, H1s, H2s and prototype H3s, along with some H4s, many of which had been in revenue service since the 1960s. The T1s had many of the same technical specifications of the H series, including the same married pair configuration, and incorporated many of the design elements that had been refined throughout the H-series program. Each model in the H-series production run improved on the last, adding features such as a single-handle controller for acceleration and braking, air conditioning, a change from camshaft to chopper control, and regenerative braking. The T1 built on those advances (such as changing from a rotary-type to a fore–aft, joystick-type controller) while integrating new computer technology (analogous to the New Technology Train of the New York City Subway), creating a more modern train. The T-series cars were the first TTC cars to use AC propulsion, rather than DC propulsion as used in all previous rolling stock, all of which are now retired. Other improvements included wider entry and exit doorways, flip-up seats for the installation of wheelchair positions (which are now marked in blue velour to signify priority seating areas instead of the red velour used for other seats), and the removal of vertical stanchions along the car's centre line, making them the TTC's first subway cars to be wheelchair-accessible. The interior colour scheme consists of grey floors and