Bloor–Danforth line
Due to the opening of the Bloor–Danforth line and the additional services that were required, a new set of trains were purchased from the Hawker Siddeley group. These trains, which were a part of the H series, were similar to the M1-series trains with newer features such as electrically operated doors. With the introduction of the T1-series subway trains, the H1 and H2 trains were retired from service, while the remaining H4 trains (along with some earlier T1 series trains) were shifted to the Bloor–Danforth line.