GT3 was a prototype mainline gas turbine locomotive. It was built in 1961 by English Electric at their Vulcan Foundry in Newton-le-Willows to demonstrate its wares to British Railways. It was designed by Vulcan engineer J. O. P. Hughes and the project was started in the early 1950s. Externally, it resembled a steam tender locomotive. In the case of GT3, the tender carried diesel fuel.