Formerly, the tail track at Henri-Bourassa station continued on to the Somerville fire training centre, a facility containing a burned-out metro car that was used to train firefighters to operate in the metro. The construction of the Laval metro necessitated the relocation of the centre to an enclosed portion of the Saint-Charles garage.

This new role is appropriate, as the garage was the scene of the tragedy of 9 December 1971 in which a collision and derailment caused a fire that killed driver Gérard Maccarone, destroyed 24 metro cars and seriously damaged the garage as well as Henri-Bourassa and Sauvé stations. This revelation of the difficulties of fighting fires in the metro (along with another incident in 1974) led to the creation of the Somerville centre, along with multiple other safety precautions.