| GWR 8000 Cathedral Class | |
| Powertype: | Steam |
| Designer: | Frederick Hawksworth |
| Builddate: | Never built |
| Whytetype: | 4-6-2 |
| Uicclass: | 2′C1′ |
| Driverdiameter: | 6feet |
| Boilerpressure: | 250psi |
| Cylindercount: | Four (two outside, two inside) |
| Cylindersize: | NaNx |
| Tractiveeffort: | 403002NaN2 |
The Great Western Railway (GWR) 8000 or Cathedral Class was a class of proposed 4-6-2 steam locomotive. This locomotive class would have been the GWR's second attempt at designing a 4-6-2 locomotive, following No. 111 The Great Bear.
The proposal for the Cathedral Class was submitted by Frederick Hawksworth in 1941. It was designed for post-war rail traffic.
The Cathedral Class would have featured similar features from other locomotives in the UK, such as having 4-cylinders, an all-new tender design from the Hall Class and 1000 County Class that would come years later, same pony truck from the King Class 4-6-0s, different trailing bogie design coming from the LMS Princess Royal Class 4-6-2 Pacifics and, the same body design from the LMS Princess Royal Class 4-6-2 Pacifics but designed with the smokebox from the GWR Star Class.
The locomotive was to have a boiler pressure of 250psi. The locomotive's tractive effort was raised from 31625lbf on the Castle Class to 40300lbf on the Cathedral Class. The 6feet driver diameter on the King Class was kept for the Cathedral Class.
The King class having already been established and refined as the 'top link' express passenger locomotive for the GWR, the business case for the Cathedral class is unclear. The Kings entered service in 1927 with a tractive effort of 40,300 lbf (179 kN), a figure matched rather than exceeded by the Cathedral proposal[1] . Although the King's tractive effort was lowered to 39,700 lbf (176.6 kN) after their first overhaul, they still proved capable of hauling the heaviest West of England expresses without assistance. Furthermore, at the Locomotive Exchange Trials in 1948, 6018 King Henry VI proved more sure-footed climbing out of Kings Cross, where pacific locomotives were apt to slip alarmingly. The King's driving wheels and boiler had also been designed together to stay within the network loading gauge, a limit that may have been exceeded with the LMS Princess Royal boiler. Postwar austerity and the precarious financial situation of the Big Four railway companies prior to nationalisation[2] may also have contributed to the decision not to proceed with a prototype locomotive of the Cathedral class.