The Great Western Railway (GWR) experimented with oil burning steam locomotives at two points in its history. A single experimental tank engine was constructed to burn oil in 1902, and 37 engines of four different classes were converted to burn oil between 1946 and 1950. Neither experiment resulted in the long-term use of oil as fuel for steam locomotives. A single pannier tank locomotive was also converted under British Rail in 1958.
GWR No. 101 was an experimental 0-4-0 side-tank locomotive built at Swindon Works under the direction of Churchward in June 1902. Initially built as an oil-burning locomotive, it was rebuilt in 1905 as a coal burner, with the cab backplate replaced by a bunker. No further engines were built to this design, and the locomotive was withdrawn and scrapped in 1911.
GWR locomotives had been designed to take advantage of high quality Welsh steam coal. Following the end of World War II, coal supplies were scarce and of poor quality as the best coal was exported. GWR CME Hawksworth obtained permission to try using oil as a fuel in steam locomotives. He modified a number of locomotives of different classes, and the results were successful enough that it was planned to turn Cornwall into an oil fired area. The Government decided that such a scheme should be extended across the country, and asked Hawksworth to provide details of the technology to other railway companies. Several million pounds were spent on the scheme before it foundered on the uneconomic cost of the imported fuel, which had to be purchased using scarce foreign exchange. All the locomotives involved were reconverted to burn coal.
In 1946, one Hall class and one Castle class, and several 2800 class engines working in South Wales were modified. (Plans to convert some 4200 class tank engines were not carried out.) The fireboxes were modified by replacing the firebars with a plate that had openings for the air supply, lining part of the firebox with high alumina firebrick to cope with the change in combustion, and mounting a single burner at the front of the firebox that directed the oil, atomized by steam, upwards towards the back of the firebox. Initial problems with the burner saw them replaced by the Laidlaw-Drew type. Tenders were altered to hold a 1800impgal tank for oil, with steam heating coils to make the heavy grade of oil used thin enough to flow. The success of the initial conversion saw the scheme extended to further Castle and Hall class locomotives, for work in Cornwall.
Oil burners had their own maintenance requirements, including the daily removal and cleaning of the atomizers to keep them effective. Overall, though, they were easier for the firemen to maintain and run than coal fired engines. Depots were re-equipped for refuelling the engines at Bristol Bath Road, Bristol St Philip's Marsh, Cardiff Canton, Didcot, Gloucester, Llanelly, Newport Ebbw Junction, Newton Abbot, Old Oak Common, Plymouth Laira, Reading, Severn Tunnel Junction, Swindon, and Westbury. Work at Banbury and Swansea was cancelled before completion.
A total of thirty-seven locomotives were converted to burn oil, starting with No. 5955 Garth Hall in June 1946 and continuing into the next year. Some locomotives carried new numbers while they were oil burners. Reconversion to coal firing started in September 1948, and was complete by April 1950. Renumbered engines went back to their old numbers.
All engines were converted back to coal firing by 1950, and regained their original numbers. However, the 1400s were never renumbered back to 4800s.
| 2832 | 4806 | |||||
| 2834 | 4808 | |||||
| 2839 | 4804 | |||||
| 2845 | 4809 | |||||
| 2847 | 4811 | |||||
| 2848 | 4807 | |||||
| 2849 | 4803 | |||||
| 2853 | 4810 | |||||
| 2854 | 4801 | |||||
| 2862 | 4802 | |||||
| 2863 | 4805 | |||||
| 2872 | 4800 | |||||
| 2888 | 4850 | |||||
| 3813 | 4855 | |||||
| 3818 | 4852 | |||||
| 3820 | 4856 | |||||
| 3831 | 4857 | |||||
| 3837 | 4854 | |||||
| 3839 | 4853 | |||||
| 3865 | 4851 | |||||
| 100A1 | data-sort-value="100A1" | Lloyds | ||||
| 5039 | data-sort-value="5039" | Rhuddlan Castle | ||||
| 5079 | data-sort-value="5079" | Lysander | ||||
| 5083 | data-sort-value="5083" | Bath Abbey | ||||
| 5091 | data-sort-value="5091" | Cleeve Abbey | ||||
| 6320 | data-sort-value="6320" | |||||
| 4907 | 3903 | Broughton Hall | ||||
| 4948 | 3902 | Northwick Hall | ||||
| 4968 | 3900 | Shotton Hall | ||||
| 4971 | 3901 | Stanway Hall | ||||
| 4972 | 3904 | Saint Brides Hall | ||||
| 5955 | 3950 | Garth Hall | ||||
| 5976 | 3951 | Ashwicke Hall | ||||
| 5986 | 3954 | Arbury Hall | ||||
| 6949 | 3955 | Haberfield Hall | ||||
| 6953 | 3953 | Leighton Hall | ||||
| 6957 | 3952 | Norcliffe Hall |
In April 1958, under British Rail, GWR 5700 Class No. 3711 was converted to burn oil, with a fuel tank installed in the bunker. The conversion was done by Robert Stephenson and Hawthorns.
In January 2024 it was announced that 4965 Rood Ashton Hall during its next overhaul alongside undergoing a retube and a reduction in its width for gauging reasons, consideration was being made to have 4965 converted to oil burning.[1] It was confirmed in March 2024 that 4965 will be converted to oil burning with its overhaul commencing in March 2024.[2]