Tags: Train.
The Southern Railway (SR) and the British Railways (Southern Region) (BR(S)) used the designation Sub to cover a wide variety of electric multiple units that were used on inner-suburban workings in the South London area. The designation ‘Sub’ was first officially used in 1941 to refer to newly built 4-car units. However during the 1940s large numbers of earlier ‘3-Car Suburban Sets’ were increased to four cars by the addition of an ‘Augmentation’ trailer and became part of the 4-Sub category.
