British Rail DP1

prototype British twin-engined diesel-electric locomotive

DP1, or Prototype Deltic is a demonstrator locomotive built by English Electric in 1955. This locomotive resulted in 22 similar locomotives being ordered by British Rail, which became their Class 55.

English Electric DELTIC prototype
The nose end of DP1 at Locomotion
Type and origin
Power typeDiesel-electric
BuilderEnglish Electric at Dick, Kerr Works, Preston
Serial numberEE: 2003
Build date1955
Specifications
Configuration:
 • UICCo'Co'
Gauge4 ft 8 12 in (1,435 mm)
Wheel diameter3 ft 7 in (1.09 m)
Length66 ft
Loco weight106 long tons (108 t)
Prime moverNapier Deltic D18-25 (2 off)
Traction motorsEE 526/A, 6 off
Cylinders18 × 2
TransmissionDiesel Electric
Train heatingStone-Vapor/Clarkson steam generator
Performance figures
Top speed90 mph (140 km/h)
106 mph (171 km/h) from 1956
Power output3,300 hp (2,500 kW)
Tractive effort90 mph gearing: 60,000 lbf (266.89 kN)
106 mph gearing: 52,500 lbf (233.53 kN)
Career
Railroad(s)British Railways
Power classType 5
NumberDP1
Official nameDELTIC
RetiredMarch 1961
Dispositionto Science Museum, London, April 1963