The British Rail Class 357 Electrostar alternating current (AC) electric multiple-unit passenger trains (EMUs) were built by Adtranz at its Derby Litchurch Lane Works, England, in two batches from 1999 to 2002 at a cost of approximately £292 million. They were the first member of the Electrostar family, which also includes Classes 375, 376, 377, 378, 379 and 387, and are the most numerous type of EMU built in the post-privatisation period of Britain's railways. They have the same basic design, bodyshell and core structure as the Turbostar diesel multiple unit (DMU), which is in turn the most common post-privatisation diesel multiple unit family, and both evolved from the Class 168 Clubman design by Adtranz. The 357s are operated by c2c on the London, Tilbury and Southend line. Description The Clubman/Turbostar/Electrostar platform is a modular design, optimised for speedy manufacture and easy maintenance. It consists of an underframe, which is created by seam-welding a number of aluminium alloy extrusions, upon which bodyside panels are mounted followed by a single piece roof, again made from extruded sections. The car ends (cabs) are made from glass-reinforced plastic and steel, and are huck-bolted onto the main car bodies. Underframe components are collected in 'rafts', which are bolted into slots on the underframe extrusion. The mostly aluminium alloy body gives light weight to help acceleration and energy efficiency. Electrostar units have a shorter version of the Turbostar's body. Class 357 units were built with capability, although the maximum line speed on the London, Tilbury and Southend line (the Essex Thameside franchise) is at present only . They all have air conditioning, air suspension, CCTV, standard class 3+2 Chapman seating throughout, 28 computers, sliding plug doors, and rheostatic and air disc brakes, and now have regenerative capacity. As with all Electrostar units, they use insulated-gate bipolar transistor (IGBT) AC motor drives. They have Tightlock fully automatic couplers but are only interoperable within their own class with other Class 357 units. There are orange LED dot matrix displays at the front of each unit which show the time due at the destination and the name of the destination, e.g. "17.10 Grays", or "Not in Service" or "Empty to Depot" as necessary. The time due at the destination updates to the new time due if the train is delayed. There are also LED displays inside, at the end of each carriage above the gangway which give route