The narrow gauge Toronto, Grey and Bruce Railway (TG&BR) was incorporated on March 4th, 1868 with a mandate to build a railway to reach from Toronto to the Grey and Bruce counties of Ontario. The ambitious plan was to build a 3 foot 6 inch narrow gauge railway from Toronto to Orangeville, Mount Forest, Durham and Southampton on Lake Huron, with a branch to Kincardine, and another from Mount Forest to Owen Sound. It was promoted by George Laidlaw, who was also involved with another narrow gauge railway, the Toronto & Nipissing, being built at the same time to the northeast of Toronto.
Construction was launched with a sod turning ceremony in Weston, Ontario on October 5th, 1869 by His Royal Highness Prince Arthur, who was on a Royal Tour at the time. On April 17th, 1871 the first train arrived in Orangeville. The first train to arrive in Owen Sound was a Director's special two years later on June 12, 1873. The branch line to Teeswater was opened November 11, 1874.
The first locomotives on the TG&BR were a 4-6-0 and several smaller 4-4-0's ordered from the Avonside Engine Company of England in the Spring of 1869. In 1872 a Fairlie 0-6-6-0 and a larger 4-6-0 were acquired as well from Avonside. Then followed two small 2-6-0's from the Baldwin Locomotive Works. The final order to Avonside was for three small and one large 4-6-0's. Late delivery of these engines from England in 1873 was responsible in large part for a subsequent locomotive order going to Baldwin for six 2-8-0's which were delivered in 1874. The most successful of all these locomotives, judged by their utilisation, were the Avonside 4-6-0's. Several of the 4-4-0's and 2-8-0's were regauged to the new standard 4' 8 ½"and continued in service with the Canadian Pacific Railway.
The Toronto terminus of the railway was at the foot of Bathurst Street between Front Street and Queen's Wharf. It ran using a third rail between the Grand Trunk's 5' 6" gauge rails as far as Weston, where it turned north.
The railway suffered from its own success. The freight volume was soon too much for the initial locomotive and car capacity. Much more equipment was bought but arrived just as freight traffic fell off due to a trade depression. The heavy cost of this capital equipment sank the railway economically. It was seized by its debtors, and operations were turned over to the Grand Trunk, which re-gauged the railway to 4' 8 ½" standard gauge and ran the railway until the early 1880's. At that point in history, the Grand Trunk encountered financial problems of its own, and the railway merged with the Ontario and Quebec Railway, a subsidiary of Canadian Pacific Railway (CPR) in 1883.