British Rail Class 357 Electrostar

The Class 357 Electrostar was a fleet of seventy-four four-car 25 kV AC electric multiple unit sets built between 1999 and 2002 by Adtranz (later Bombardier Transportation) at Derby, ordered by c2c (originally LTS Rail) for the demanding London Fenchurch Street to Southend-on-Sea and Shoeburyness services on the former London, Tilbury and Southend Railway. The Fenchurch Street lines had historically operated one of the most intensive and heavily-loaded suburban services in Britain — the line was notorious for its peak-hour overcrowding and the remarkable frequency of its trains — and the Class 357 was built to replace the ageing Class 310 fleet that had worked these services since the early days of WCML electrification.

The Class 357 was the first production order for the Bombardier Electrostar platform — a new-generation aluminium-bodied EMU design that represented a significant departure from the BREL York steel-bodied standard of the previous two decades. The Electrostar body was wider than its BREL predecessors (2.80 metres), lighter through its aluminium construction, and designed to a higher standard of passenger comfort with better seating, improved accessibility, and full air conditioning. The traction equipment used IGBT inverter technology driving three-phase asynchronous traction motors, giving smooth, efficient acceleration well suited to the high-frequency, closely-spaced stopping pattern of the Fenchurch Street services.

Seventy-four sets were delivered in two subclasses: the 357/0 (357001–357046) as the initial c2c order, and the 357/2 (357201–357228) as an additional batch for fleet expansion. All sets have been allocated to East Ham depot throughout their service lives and have worked the Fenchurch Street network exclusively. Under the various franchise arrangements the service has operated as LTS Rail, c2c, and National Express c2c, all maintaining the characteristic purple and orange livery that became the visual identity of the Fenchurch Street lines from 1999 onwards.

The Class 357 fleet has proved remarkably durable and has undergone several refurbishment rounds that have maintained the passenger environment. As of 2026, the entire fleet remains in active service with c2c, over twenty-five years after the first sets entered traffic. The Fenchurch Street lines continue to be among the most intensively worked in Britain, and the Class 357 remains central to their operation.