From the Transit Toronto fanpage:

The Scarborough RT did attract more passengers than buses could comfortably serve, but it also ran into controversy. […] The turning loop at Kennedy station was a particular problem. Designed for streetcars, the linear-induction trains had difficulty handling its tight curves. The speed limit was reduced on the loop to just 5 km/hr after a derailment occurred during operation. In total, problems led the TTC to ask the province for $27 million to repair issues and to rebuild the turning loop and platforms at Kennedy station.

The province, to its credit, agreed to pay for the costs, and the SCARBOROUGH RT shut down for three months during the summer of 1988. A switch was added at the east end of Kennedy station to allow trains to cross over. The loop was taken out of regular service and used to store trains in an emergency. The platform at the south side of the station was extended across its adjacent track to the former inbound track, allowing arriving trains to open doors on both sides. Boarding passengers would board trains from the south platform while disembarking passengers would depart on the north platform, heading downstairs to the bus terminal.