Due to the loss of the majority of the United Kingdom's tank force in France, tank production in the UK at the start of the war was insufficient to supply Canada as well, so it was decided to manufacture locally. The Montreal Locomotive Works, which was a subsidiary of the American Locomotive Company, was designated the Canadian Tank Arsenal. Initial production was of Valentine tanks, many of which would be supplied to the USSR. Although the Valentine used a number of US produced parts, limitations in the availability of armour plate affected Valentine production. The Canadians were interested in production of the M3 Medium, and the British Tank Mission contributed a tank expert to design a new hull that could take a larger turret while retaining the lower hull of the M3. The new hull was cast rather than welded or rivetted and lower than that of the M3.
| Ram Medium Tank Cruiser | |
|---|---|
| Type | Medium tank |
| Place of origin |  Canada |
| Service history | |
| Used by | Canada |
| Wars | Second World War |
| Production history | |
| Designed | 1941 |
| Produced | 1941–43 |
| Specifications | |
| Weight | 29.5 m |
| Length | 5.79 m |
| Width | 2.67 m |
| Height | 2.9 m |
| Crew | 5 (Commander, gunner, loader, driver, co-driver/hull gunner) |
| | |
| Armour | 87 mm |
| Main armament | Mk III QF 6 pdr (92 rds.) |
| Secondary armament | 2 × .30 cal machineguns (4,440 rds.) |
| Engine | Continental R-975 9-cyl radial gas 400/340 hp (298/254 kW) |
| Suspension | Vertical volute spring |
| Operational range | 232 km |
| Speed | 25 mph (40 km/h) |
Canadian engineers however ran into several problems when developing the tank. The Ram tank was developed with a turret which could traverse in mind, a full cast iron hull for reinforced protection, a lower ride height, and good reliability. Many Canadian engineers however did not know how to produce such equipment. Canada had never produced a tank before. Along with the lack of knowledge, supplies were not within Canadian factories and Canada relied heavily on United States and British materials to complete the construction of the Ram.
Although the ability to mount a large 75 mm gun was suggested, the turret was built to take the QF 6 pounder. As it was not immediately available, early production (55 tanks) were fitted with the two pounder gun.
A prototype Ram was completed in June 1941. General production of the Ram I began in November of the same year. This was fitted with side doors in the hull and an auxiliary machine gun turret in the front - these features would be discarded in later modifications. By February 1942, production had switched to the Ram II model with a 6-pounder gun and continued until July 1943, when a decision was made to adopt the Sherman tank for all British and Canadian units. By that point 1,948 vehicles, including 84 artillery observation post vehicles, had been completed.
