British Rail 11001

11001 was one of the first British Railways diesel locomotives, built in 1949 at British Railways' Ashford railway works. It was designed by Oliver Bulleid when he was Chief Mechanical Engineer of the Southern Railway. It was powered by a Paxman RPH Series 1 engine, capable of delivering 500 bhp at 1,250 rpm. It was driven via a Vulcan-Sinclair fluid coupling to an SSS (synchro-self-shifting) Powerflow gearbox. The gearbox provided three forward and reverse gears in either high or low range, with top speed ranging from 5 mph in 1st gear, low range up to 36 mph. It had a 0-6-0 wheel formation, driven by rods from a rear jackshaft on the final drive, and with Bulleid's favoured BFB wheels.

Its main duties were on branch lines and shunting, working dwindling goods services on the Caterham line during the 1950s. It was allocated to Norwood Shed, but also has been photographed in Swindon. It was withdrawn in August 1959 and scrapped at Ashford Works in December.

Unusually, the locomotive's controls were laid out as in a steam locomotive, possibly due to few drivers having experience with diesels at the time. There are no known photographs of the interior.