Originally planned as Toronto's first LRT, the Provincial government at the time decided to use the line as a showcase for ICTS technology, being developed by Urban Transportation Development Corporation (UTDC), an Ontario crown corporation (since purchased by Bombardier). The Scarborough RT was planned to be just the first of several ICTS lines in the Greater Toronto Hamilton Area (GTHA) including the Etobicoke RT and a line in Hamilton. Evidence of the Etobicoke RT can be seen in the flat area on the south side of the upper level of Kipling Station, which was planned to be the RT platform. Ultimately however, the Scarborough RT became an orphan technology in the TTC system.
Shortly after the SRT was opened in March 1985, Vancouver opened their SkyTrain system in December of that year. While the SkyTrain system has been expanded and upgraded significantly since its debut, the SRT has stayed more or less the same. While Vancouver is in the process of phasing out its Mark I vehicles in favour of Mark II and Mark III vehicles, the Scarborough RT is still using exclusively Mark I. The underground curve just north of Ellesmere Station has too sharp of a radius to accommodate the newer, larger vehicles, and would need to be rebuilt if they were to be introduced.