Experience with the Maunsell 350hp Diesel Electric Shunters built in 1937 and the subsequent Bulleid versions built from 1949 showed that whilst 350hp was more than capable for the shunting duties they were not either powerful, or fast enough for trip (pick up goods) working amongst the frequent passenger services on the suburban lines around London.

photograph: Graham R 'Muz' Muspratt collection

The design of 11001 was therefore intended to be able to overcome some of these issues with its greater power of 500hp and higher speed. It should be noted, perhaps surprisingly, that its Tractive Effort at 33,000lb was the same as a Bulleid Q1.

11001 was completed at Ashford in 1950. Unlike the earlier 350hp diesel electric locomotives it had a totally mechanical drive comprising of a Paxman Ricardo V12 12RHP engine coupled to a two range, three speed gearbox though a Sinclair fluid coupling. Final drive was via a jackshaft. Its body styling was quite unique with a long bonnet, which unusually housed the fuel tank at the front end rather than a radiator, and a very high arc cab roof with large angled front windows. The 4' 6" wheels, in common with other Bulleid designs of the time, were of the Bulleid-Firth Brown type.

photograph: Graham R 'Muz' Muspratt collection

In the high-speed range it was originally intended to be able to run at a maximum speed of just below 45 mph. It turned out however to be neither a shunter nor a trip engine. The low-speed range was too inflexible for shunting, and the high-speed range, with only three gear steps, was too low for line duties. It worked from Norwood for a time, but unfortunately spent a long time out of service and was finally withdrawn in 1959.
It was originally painted in BR loco black that was later amended to green.

photograph reproduced by arrangement with Honeywood Heritage Centre, Carshalton, courtesy of Tony Price

Technical Details

• Built by: Ashford
• Introduced: 1950
• Number Series: 11001
• Engine: Paxman Ricardo V12 12RPH 500HP
• Transmission: Mechanical
• Gear Ratios: Low - 1st - 39.6:1, 2nd - 22.38:1, 3rd - 13.35:1 - High - 1st - 16.59:1, 2nd - 9.374:1, 3rd - 5.589:1
• Maximum Speed: 43½ MPH
• Weight: 50 tons
• Height: 12 ft 11½ ins
• Length: 33 ft 3 ins
• Width: 8 ft 7½ ins
• Cylinders: Bore 7 ins, Stroke 7¾ ins
• Wheel Diameter: 4 ft 6 ins
• Wheelbase: 12 ft 6 ins
• Minimum Curve Negotiable: 4 chains
• Braking: Air (no train brake)
• Fuel Tank: 606 gals
• Cooling Water Capacity: 60 gals
• Sanding Equipment: Pneumatic
• Tractive Effort: 33,000 lbs
• Power at Rail: 410 hp