This foundry’s importance was in the role it played in the manufacture of rolling stock for pioneer railway systems and castings and sewer pipes for municipal services and the construction industry.
William J. Hamilton was a Scotish iron founder, who moved to Toronto in 1850. After working for a short time for James Good and stove-maker J.R. Armstrong, he leased property in this block in 1851 and began to develop the St. Lawrence Foundry. In 1856, he was joined by his son, William M., in a partnership called William Hamilton and Son. When it started they specialized in the manufacture of castings of all kinds for buildings and industrial uses. By 1871 the foundry complex filled the entire block. In 1870, the Toronto and Nipissing Railway engaged this foundry to construct 88 passenger and freight cars, and in the following year to construct 100 cars. Orders from other companies followed: the Toronto Grey and Bruce Railway, the Grand Trunk Railway, the Northern Railway of Canada, the Midland Railway, the Intercolonial Railway, and from the Canada Rolling Stock Company, a railway car leasing firm. In 1873, they opened the St. Lawrence Car Wheel Foundry on the northwest corner of Front and Cherry Streets. By this date, the original foundry building was surrounded by other structures: many sheds, an office, a bolt and spike shop, a car factory, a boiler room, a machine shop, a shed workshop, and at the southwest corner of the block a house.
Economic reversals later in 1873, forced a reassement. All car production was stopped and the car wheel division was sold to the Toronto Car Wheel Company. A fire, November 21, 1876, destroyed most of the foundry .Some portions and equipment were saved and some rebuilt. In 1878 William J. turned over the company to his son, who reorganized the firm as the St. Lawrence Foundry Company of Toronto Limited, and consentrated on the manufacture of castings, sewer pipes, etc. The last Hamilton to be associated with the company was Frederick J., After the company was sold in 1900, it became an arm of Canadian General Electric, manufacturing cast iron pipes. The plant was closed and vacant by 1917, later to be demolished.
Information from “A Glimpse of Toronto’s History” MPLS # 180