Class 377 [Updated]

The "Electrostar" Class 377 is the largest fleet of EMUs built since rail privatisation and has replaced 4-Cig and 4-Vep EMUs on commuter services around London and rural services in the South East. Although their class number is in the 3xx series most collect electric current via the 750v DC 3rd rail system though some have pantographs. These can also collect current from 25kV AC overhead lines for cross-London services and can venture up as far as Milton Keynes and St. Albans. Some Class 377s have been converted from the similar Class 375 as detailed below.

Number built: 211 sets (plus 28 sets converted from Class 375)
Built: 2002-
Builder: Bombardier Derby
Engine: 6 or 4 Bombardier traction motors
Power: 2, 120 hp (1, 500 kW) or 1, 341 hp (1, 000 kW)
Formation: Driving Motor Composite Open (DMCO)+Motor Second Open (MSO)+
Trailer Second Open (TSO)+DMCO

They are in service with Southern and Thameslink and more will be built over the next few years. The fleet is split into a number of sub-classes.

Sub-class Details
377/1 Original, third-rail DC 4-car operated by Southern
377/2 Dual voltage 4-car operated by Southern and Thameslink
377/3 Third rail DC 3-car units converted from Class 375s operated by Southern
377/4 Third rail DC 4-car operated by Southern
377/5 Dual voltage 4-car operated by Thameslink
377/6 Third rail DC 5-car operated by Southern
377/7 Dual voltage 5-car operated by Southern

Southern 377 612 at London Bridge

Southern 377 440 at Clapham Junction

Southern 377 701 at West Brompton