This fleet completed delivery in August 2005 from Bombardier Transportation, Derby. They are 100 mph “outer suburban” units, offering a high interior standard with air conditioning, passenger information systems, and full compliance to RVAR and the latest safety standards. The units are progressively being fitted with Dellner Couplers (Based on Scharfenberg design) replacing the original tightlocks. Electrical connections remain common to the original coupler, hence they can be converted back if required to run with South Eastern Class 375 units. Inter-unit gangways are provided, also compatible with 375s, and power doors by IFE. Six 250kW ac motors are powered by three IGBT drive packages, providing a highly reliable and safety approved traction system. Construction is all aluminium with extrusions huck bolted together to form a strong tube assembly. The Electrostar fleet includes the Class 357 ac version and is the largest passenger fleet in Porterbrook’s portfolio. Some units are built with dual voltage capability, however the majority are suitable for conversion if required. .