Culture Division of the City of Toronto
http://www.toronto.ca/culture/
The TRHA is working closely with the Culture Division of the city of Toronto in the formation and development of the Toronto Railway Museum as it will be a city museum.
Parks and Recreation Department of the City of Toronto
http://www.toronto.ca/parks/
The TRHA is working closely with the Parks and Recreation Division of the city of Toronto in the formation and development of the Roundhouse Park as an element of the Toronto Railway Museum as the park is a city park.
Toronto Locomotive Preservation Society (TLPS)
A key component of the Railway Collection of the city of Toronto is CNR Steam Locomotive No. 6213, a 4-8-4 Northern. It has been lovingly maintained for many decades by a small group of dedicated volunteer preservationists who form the Toronto Locomotive Preservation Society (TLPS)
Toronto & York Division of the Canadian Railroad Historical Association
The Canadian Railroad Historical Association is the preeminent national organization in Canada dedicated to preserving the history of Railrays in Canada. The CRHA has numerous local chapters across the country that they call "divisions". Toronto & York Division has been leading this effort for many decades in the Toronto.
Heritage Toronto
http://www.heritagetoronto.org/
The TRHA offers regular railway heritage walking tours as part of Heritage Toronto's Walks program.
Steam Whistle Brewing
http://www.steamwhistle.ca/
The brewery occupies stalls 1-11 of the roundhouse and is currently expanding into stalls 12-14. Every year, Steam Whistle makes their facilities available for TRHA displays during Doors Open weekend.
Toronto Terminals Railway (TTR)
http://www.ttrly.com/
This is the TTR website with information about Union Station and the train operations associated with it. The TRHA conducts regular public tours of Union Station in partnership with the TTR.