To form the backbone of GO’s coach fleet, Hawker Siddeley was contracted to construct the fleet of single level coaches with 4 batches being delivered between 1967 and 1976.

Based on Hawker’s existing H-series of TTC subway cars and designated RTC-85, 123 cabs and coaches were built. Additionally, 8 self-propelled RTC-85SP cars were also delivered, but due to reliability issues would be de-motored by the mid 1970s and repurposed as cab cars.

Due to the overwhelming success of GO, coupled with rapid expansion, the single level cars proved to be too small to handle the volume of commuters and GO quickly began testing gallery cars from Montreal (CP) and Chicago (C&NW). Settling on an all-new multi-level design from Hawker (now the Urban Transit Development Corporation), these new cars supplanted the single level cars beginning in the mid-80s with the final cars withdrawn in the early ‘90s.

While the new multi-level fleet was being constructed, many of the single levels were leased out to US agencies. The Massachusetts Bay Transportation Authority leased 48 between 1978-80 and returned for 51 between 1984-85. Maryland’s MARC leased some as well in the mid-70s.

Upon retirement, the single levels still had lots of life left in them and most found second homes. Ontario Northland purchased 23 to reequip many of their passenger operations such as the Northlander and other regional services. Heavily rebuilt for long distance service, many in the fleet continue to operate today.

Montreal’s AMT also picked up most of the remaining coaches and cabs in 1994 with most remaining in service well into the mid-2010s.

While most of the Hawker single-level fleet has been scrapped now, car 104 was restored to its former GO livery and is now on display at the Toronto Railway Museum.