Class 91

Finally in the 1980s BR got the go-ahead and funds for the electrification of the East Coast Main Line (originally it was supposed to have taken place at the same time as the WCML), for this they needed a new fleet of express passenger locomotive. These were the Class 91 which were coupled to Mark 4 coaches with a Driving Van Trailer on the other end [1]. This system was also called the Intercity 225 (replacing the Intercity 125 as it did on the ECML) though the trains couldn't go 225mp/h, just a mere 140mp/h! However this has been restricted to 125mp/h in everyday use, on a test train one Class 91 has reached 162mp/h in 1989 (the British locomotive speed record).

Number built: 31
Built: 1988-91
Builder: BREL Crewe
Engine: GEC G426 traction motors (25kV AC OHLE)
Power: 6, 080 hp (4, 533 kW)
Wheel arrangement: Bo-Bo

Unusually the Class 91 is asymmetric with a streamlined cab at one end and a blunt ended one at the other. It can operate fully in either direction though of course usually travels pointy-end first, especially when hauling an express. The blunt end cab is fully operational and indeed the Class 91 can travel at up to 110mp/h this way around. As built the Class 91s were 91/0s but became 91/1s after refurbishment [2].

They remain on express duties on the ECML though will be replaced by a new generation of high speed trains in the next few years. They are currently operated by Virgin East Coast, before that East Coast, NX East Coast, GNER and BR Intercity. What happens to them next is currently unknown, although their reliability could be better it is likely they will find further use cascaded to other routes.
Virgin EC 91 109 at Kings Cross

91108 in East Coast livery at York

[1] Gavin Morrison, AC Electric Locomotives (Ian Allan, 2013) p. 80
[2] Colin J Marsden, Traction Recognition (Ian Allan, 2011) p. 92