In 1942 it seems the Canadian National Railway were looking for ways to use the exhaust steam generated by the heating system, the laundry and kitchen operations. Their solution was to dig a tunnel 400 feet long to the Georgia Medical Dental building and the Devonshire hotel across the street and run heating pipes to both buildings. The move saved the hotel 500 tons of coal a year and it meant two other heating plants could close.
Careful blasting and digging 25 feet below the surface created the tunnel that carried six and eight inch pipes.