Steam Cardiff Canton was opened in June 1882 as a six road, -long shed, built to replace Long Dyke, east of
Cardiff General station. The GWR enlarged the depot in 1897 with a -diameter turntable installed in a square locomotive shed with 28 roads radiating off the turntable. In 1925 the GWR added a locomotive repair and lifting shed and a new coaling stage. In 1931 the original -turntable was removed and replaced by a larger -diameter one at the west end of the yard. At this time, around the peak of GWR operation, the depot had allocated 50 main line passenger locomotives, 40 heavy goods/
mineral locomotives and 30 smaller local passenger/goods and shunting locomotives. Steam traction at the depot ceased on 8 September 1962.
Diesel In the winter of 1962–63, Kyle Stewart contracted to build for
British Railways a new £1,324,000 complex on a site.
Lord Brecon,
Minister of State for Welsh Affairs, opened the new depot on 18 September 1964. The original allocation was 360 locomotives for major maintenance, 197 for normal maintenance and 62 shunting locomotives. Employed were 40 managerial and supervisory staff, 31 clerical staff, 382 maintenance staff and 55 unskilled staff. In 1987, the depot's allocation of rolling stock included Classes
08,
37,
47,
56 and
DMUs, although Classes
33 and
50 could also usually be seen at the depot. ==Allocation==