British Rail Class ES1

North Eastern Railway Class ES1
NER No.1, Locomotion museum, Shildon
Type and origin Power type Electric Builder British Thomson-Houston, with mechanical parts sub-contracted to Brush, for North Eastern Railway Build date 1903-1904 (contract signed with builders on 15 December 1902) Total produced 2
Specifications Configuration: ​  • Whyte Bo-Bo  • AAR B-B  • UIC Bo+Bo Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Wheel diameter 3 ft 0 in (0.914 m) Wheelbase 27 ft 0 in (8.230 m) Length 37 ft 11 in (11.557 m) Height with pantograph lowered 12 ft 11 in (3.937 m); raised 15 ft 9 in (4.801 m) Loco weight 56 long tons (57 tonnes; 63 short tons) Electric system(s) 600–630 V DC, Third rail or catenary Current source Contact shoe or pantograph Traction motors British Thomson-Houston, 4 off Train heating None
Performance figures Maximum speed 27 mph (43 km/h) Power output 640 bhp (477 kW) Tractive effort 25,000 lbf (111.2 kN) 335 t (330 long tons; 369 short tons) @ 14 mph (23 km/h)
Career Operators North Eastern Railway London and North Eastern Railway British Railways Numbers NER: 1–2 LNER 1–2, later 6480–6481 BR: 26500–26501 Axle load class Route availability 2 First run 1905 Retired 1964 Disposition No.1 preserved, No.2 scrapped in 1966

British Rail Class ES1 (Electric Shunting 1)is a class of two electric locomotives commissioned by the North Eastern Railway in 1902. They were of steeplecab design.

Both locomotives passed to the London and North Eastern Railway in 1923 and then to British Railways in 1948, but both were withdrawn before TOPS.

The North Eastern Railway was an enthusiastic and relatively early adopter of electric traction for railways. As part of a 1902 scheme to electrify the suburban railway networks in the Tyneside area, the NER's Chief Mechanical Engineer, Wilson Worsdell, also wished to electrify a ³⁄₄-mile (1.2 km), horseshoe-shaped freight line that went from Trafalgar Yard in Manors to Newcastle Quayside Yard. Passing through three tunnels, this line had gradients as steep as 1:27 (3.70 %) and a number of sharp curves: it presented a formidable challenge for steam traction. Working conditions inside the tunnels were atrocious because the locomotives had to work exceptionally hard to manage the gradients which meant they produced vast quantities of choking fumes that could not disperse from the tunnels; the sparks they produced were a constant fire risk to the flammable packing materials in the yards. Electrification was the obvious answer.

The specification for new electric locomotives demanded that they be able to start a train of 150 tons on the steepest gradient, while on the level they were expected to be able to haul 300 long tons (305 t; 336 short tons) at 14 mph (23 km/h). The end-to-end journey on the branch was to be completed in 4.5 minutes.

In 1900 General Electric (GE) and Thomson-Houston designed and built a locomotive of the steeplecab type for the Milan-Varese railway in Italy, electrified at 650 V DC using the third rail system. That railway opened in 1901, and the locomotive design proved successful. The North Eastern Railway's ES1s were derived from that American design, although they were designed from the start for both third rail and overhead operation: the Newcastle Quay branch used both systems—third rail in the tunnels, and overhead lines on the rest of the line.