renumbered into the departmental series. The two Class 446 power cars were teamed with a newly built pantograph trailer and became TOPS Class 920, number 920001. This was then used for the development of Classes 313-315. The two Class 445 four car sets became TOPS Class 935, numbered 056 and 057 in the Southern Region departmental (non-revenue earning) unit series. 056 saw little use, being stored at Wimbledon Park until June 1980, when it was transferred to the Railway Technical Centre at Derby. Production classes The production-run classes which are most visibly similar to the PEP Stock are the dual voltage 750 V DC / 25 kV AC Class 313, the 25 kV AC Classes 314 and 315, and the 750 V DC Classes 507 and 508. It was also planned that the rolling stock for the services through the proposed Picc-Vic tunnel, intended as Class 316, would have formed part of the PEP family. However, subsequent builds have also drawn heavily on the experience gained by this stock. The PEP units had three sets of sliding doors on each of the non-driving cars for handling dense inner-suburban traffic. However, the Class 313 and all subsequent builds, including later Mark 3-based units, have only had two sets of doors per car. Disposal All three units were finally taken out of use in the mid-1980s. None of the cars have survived; 920001 was scrapped in 1987, 056 in 1986 and 057 in 1990. Formations The unit formations in passenger and departmental service were: References Sources Further reading External links 445 445 British Rail Departmental Units Train-related introductions in 1971 750 V DC multiple units