The Class 507 is a type of electric multiple unit (EMU) train built by British Rail Engineering Limited at York Works in two batches from 1978 to 1980. They were the second variety of British Rail's standard 1972 design for suburban EMUs derived from PEP stock, which eventually encompassed 755 vehicles and five Classes (Class 313/314/315/507/508). The 507s were the first variant to be 750 V DC third rail only. They have worked on the Merseyrail network from new, and continue to do so, having been refurbished by Alstom's Eastleigh Works.