British Rail Class 377

The Class 377 Electrostar is a British electric multiple-unit train (EMU) built by Bombardier Transportation at its Derby Works, from 2001 to the present. The Electrostar family, which also includes Classes 357, 375, 376, 378, and 379, is the most numerous type of EMU built in the post-privatisation period of Britain's railways. The class forms the major part of the Southern fleet.

Description
The units work suburban services in south London, and rural commuter services to Sussex, Surrey, Kent and the South Coast, on which they replaced 4Cig and 4Vep slam-door stock which came to end of their useful lives and which did not meet modern health and safety requirements. Built in the early 2000s, the units had a troubled introduction; being fully air-conditioned, their higher power consumption compared to the slam-door Mark 1-based stock that they replaced led to major upgrades being required to the 750 V DC third-rail power supply used in the former Southern region. The collapse of Railtrack following the Hatfield accident further delayed this upgrade work, and the new stock did not enter squadron service until 2003.

Class 377s are fitted with external CCTV. There is a disabled seating area, and both intermediate coaches have toilets. Bodyside power doors are electrically operated, a move away from the air powered systems of previous generation EMUs. Dual-voltage units are fitted with a Brecknell Willis high-speed pantograph, incorporating a pair of aerofoils on the pan knuckle to steady the pan head against the OLE contact wire. The configuration of a 5-car Class 377 unit is:


 * DMOS(A) - 2 motors on inner bogie, sander, auxiliary converter module
 * MOSL - 2 motors on inner bogie, standard toilet
 * PTSOL - pantograph, transformer, compressor, disabled toilet
 * MOS - 2 motors on inner bogie, standard class interior (at present this is only found on class 377/6 units)
 * DMOS(B) - 2 motors on inner bogie, sander, auxiliary converter module

In 4-car units the driving cars are composite, with the first-class saloon between the driving cab and the first set of passenger doors. 4-car units also do not contain the MOS coach.

MITRAC
Mitrac is the Bombardier Train Management System (TMS). It provides monitoring of on-train systems, fault-finding diagnostics, event monitoring, and preventative maintenance. In conjunction with the onboard GPS receiver, Mitrac controls Selective Door Operation (SDO), as well as automatic Passenger Information System (PIS) displays and Public Address announcements. Engineers can access the system remotely via GSM to download the fault log, then carry out real-time diagnostics while the train continues in service.

Couplers
The Class 377 uses Dellner couplers instead of the Tightlock type originally used on Southern's Class 375s. Southern's 375s were all converted to Class 377/3s - these reclassified units can still be identified by their 3-car formation. Note that Southeastern's 375s (sub-classes 375/3, 375/6, and 375/7) were also converted to Dellner couplers, but not reclassified; its 375/8 and 375/9 units were fitted with Dellner couplers as built.

Traction current supply
All units can receive power via third-rail pick-up which provides 750 V DC. There are eight pick-up shoes per unit (twice the number of previous generation 4-car Electric multiple units), and this enables them to ride smoothly over most third-rail gaps. The units in the 377/2 and 377/5 sub-classes are dual-voltage, and are fitted with a pantograph to pick up 25 kV AC from overhead lines. On these units the shoe mechanism is air-operated so that when powered down, or working on AC overhead lines, they are raised out of the way. This is used on trains from Milton Keynes to South Croydon which use part of the West Coast Main Line between Milton Keynes and Willesden Junction, and then the West London Line towards Clapham Junction. These trains change to third-rail DC supply on a dual-voltage section of the West London line north of Shepherd's Bush. Since March 2009, dual-voltage Class 377 sets have also been operating some Thameslink Bedford to Brighton, Rochester and Ashford services. (See below).

Among the remaining units, the trailer coach in each unit has a recess in its roof where a pantograph could be fitted, to allow for future conversion to overhead AC power. Despite most units being DC-only, the class is numbered in the 3xx series normally used for AC units.

Additional units and the Thameslink Programme
In April 2007, as part of the Route Utilisation Strategy for the Brighton Main Line, it was announced that Southern would procure an additional 48 Class 377 carriages to replace an identical number of Class 319 carriages (12 4-car units) due to be transferred to First Capital Connect. Eleven further dual-voltage units were then added to the order, making a total of 23. They were ordered from Bombardier in March 2008 and were delivered in First's corporate colour scheme but with Southern spec interior (green seats). The units were commissioned at Southern's Selhurst depot in South London before being transferred to First Capital Connect's Bedford Cauldwell depot. The first of these, unit 377501, was delivered to Cauldwell depot on 27 February 2009 after making its first appearance through the Thameslink Central London core. The 377/5s operate mainly on Bedford to Brighton services but in the peaks form part of FCC's and Southeastern's new joint service to places such as Rochester and Ashford. Once FCC's new passenger vehicles come into service, the 377/5 fleet will be returned to Southern.

Delays in the construction of the Class 377/5s for First Capital Connect saw the temporary transfer of eight of Southern's Class 377/2s to FCC to enable them to implement the planned timetable changes on 22 March 2009; the loss of these units until September 2009 was covered by the temporary cascade of a number of Class 350/1s to Southern from London Midland, which operated services between East Croydon and Milton Keynes.

In September 2011 it was announced that Southern had begun the procurement of 130 vehicles, due to delays in the procurement of new Thameslink rolling stock that would prevent transfer of the 377/5s in time for the December 2013 timetable change. The contract was awarded to Bombardier in December 2011. Nearly a year later, the option to build a further 40 vehicles was taken up; a total of 34 5-car 377 Electrostar units are under construction in Derby. These additional eight five-car units are dual-voltage and known as 377/7s.

In December 2011 three Class 377/2 units transferred from Southern to First Capital Connect to allow more 12-car services to be run.

During mid 2013, the first of the new class 377/6s arrived from Derby for type testing, and since October 2013, these units have been used in passenger service, initially on a peak hours London Bridge-West Croydon diagram. The /6 subclass has clear external differences to the previous subclasses, most notably windows set in frames instead of the more expensive ribbon glazing of earlier units.



Southern

 * Mainline and Redhill Routes: London to Brighton, Horsham, Reigate, Tonbridge, Eastbourne, Ore, Portsmouth, Southampton, Littlehampton, Bognor Regis
 * East Coastway: Brighton to Eastbourne, Hastings and Ore
 * West Coastway: Brighton to Portsmouth, Littlehampton, Bognor Regis and Southampton
 * West London Line: South Croydon – Milton Keynes Central
 * Oxted Line: London to East Grinstead
 * Outer Suburban services: Central London to Tattenham Corner, Horsham, Dorking, Guildford & Epsom Downs (selected workings)
 * Inner Suburban services: Central London to Caterham, Sutton, Epsom, West Croydon, Beckenham Junction via Crystal Palace, Mitcham, Sydenham, Peckham Rye or Norbury (selected workings)

First Capital Connect

 * Thameslink: (Brighton-Gatwick Airport-London-Luton-Bedford also Bedford to Ashford/Rochester in peak hours)

London-Brighton speed record
On 11 September 2005, units 377472 and 377474 set the record for a London Bridge to Brighton run of 36 minutes 56 seconds.