London Underground D78 Stock

London Underground D78 Stock
Refurbished D78 Stock train at West Ham in 2014
The interior of a refurbished D78 Stock car
Stock type	Subsurface
In service	28 January 1980 – 21 April 2017 (London Underground) 1 November 2021 – present on Island Line (as Class 484)
Manufacturer	Metro-Cammell
Built at	Washwood Heath, England
Replaced	O and P Stock R Stock
Constructed	1978–1981
Refurbished	Bombardier (at Derby Litchurch Lane Works) 2004–2008
Number built	75 sets (450 cars)
Successor	S7 Stock
Formation	3 cars per unit, 2 units per train
Capacity	821 per train
Lines served	District
Specifications
Car length	DM 18.37 m (60 ft 3 in) UNDM/T 18.12 m (59 ft 5 in)
Width	2.85 m (9 ft 4 in)
Height	3.62 m (11 ft 11 in)
Maximum speed	72 km/h (45 mph)
Weight	DM 27.46 tonnes (27.03 long tons; 30.27 short tons) UNDM 26.11 tonnes (25.70 long tons; 28.78 short tons) T 18.40 tonnes (18.11 long tons; 20.28 short tons)
Traction system	Pneumatic single camshaft (GEC Traction)
Traction motors	LT118 DC motor (Brush Traction)
Seating	280 per train

The London Underground D78 Stock, commonly referred to as D Stock, was a type of sub-surface rolling stock which operated on the District line of the London Underground, except on the Wimbledon to Edgware Road service. The first units were withdrawn in January 2015 with the last withdrawn on 21 April 2017.