The Southern Railway (SR) gave the designation 4Lav to the electric multiple units built to work the semi-fast services on the route between London and Brighton. None of these units survived long enough in British Rail ownership to be allocated a TOPS class.

Construction

The 4Lav (4-car Lavatory stock, numbers 2921-2953) units were built in 1932 for use on the newly electrified London Victoria to Brighton line, operating the slower services over the route. Despite the prominence given to the lavatory provision in the SR designation, there was actually only one lavatory in the whole four-car unit, and due to the lack of corridors in the unit, only passengers in that coach had access to it! Units 2954 and 2955 were added to stock in 1940. The original units were numbered 1921-1953 before the January/February 1937 renumbering of SR EMUs.

Formations

Initial formations of these units were as follows (cars not always formed in numerical order):

Withdrawal

The majority of the 4Lav units were withdrawn from ordinary passenger service in 1968, with the final few going in April 1969. Almost all the units were scrapped, but some of the 1940-built cars survived in departmental (non-revenue earning) use for several more years. However, no 4Lav stock exists today.