Rolling stock of Network SouthEast

Network SouthEast (NSE), the sector of British Rail which ran passenger services in London and southeast England between 1986 and 1994, operated a wide variety of rolling stock during its existence. The majority of the network was electrified, and further electrification schemes took place during the 1986–1994 period; and the 7,000 vehicles owned by NSE in 1986 consisted of a mixture of electric, diesel-electric and diesel multiple units, diesel locomotives and the coaches they hauled.

Network SouthEast inherited a large fleet of electric multiple units (EMUs), smaller numbers of diesel (DMU) and diesel electric (DEMU) multiple units, and some diesel locomotives and coaching stock.^[1] Much of the fleet was introduced after the 1955 Modernisation Plan; stock was old (some dated from before World War II) and in variable condition, giving a "drab" and "uninspiring" appearance, and was difficult to convert to driver-only operation.^[2] Accordingly, the sector invested in many new vehicles during its eight-year history. After initial problems, the Networker range of units proved very successful and is still used across southeast England on the privatised rail network. The same applies to the innovative Class 319 dual-voltage units, built for NSE's new Thameslink service which operated on two incompatible types of electrified line.^[3]