Rolling stock of Network SouthEast

[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.

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.

During the four-year life of this sector—Network SouthEast's immediate predecessor—the number of passenger-carrying vehicles allocated to it was reduced steadily as timetables were adapted in response to a decline in demand caused by the recession.

By 1990, NSE had nearly 100 more EMU coaches but fewer DMUs and a near-halving of locomotive-hauled stock; and 80% of carriages had a public address system and 33% featured sliding doors.

[14] Rolling stock of all types was painted in the network's "house colours" of red, white blue and grey horizontal bands, swept up diagonally at the end of each unit.

This would be a family of closely related classes of diesel and electric rolling stock which shared design and engineering features such as lightweight aluminium alloy bodywork (instead of steel), fully automatic couplings, computer-controlled traction motors, passenger-operated sliding doors and new high-backed seating laid out to give more space around the doors.

After visiting Derby in 1986 and investigating the concept, Green committed to buying large numbers of the trains (to be called "Networkers") for NSE in two stages.

Meanwhile, a full-size wooden mock-up of a Networker was unveiled at the end of 1987 at London Victoria by Secretary of State for Transport Paul Channon.

In August 1989 a £690 million contract was signed for the delivery of 842 vehicles and the construction of a maintenance and storage depot at Slade Green near Dartford.

[22] The Class 465 and 466 units (the latter identical to the more numerous 465s, but built by Metro Cammell at Washwood Heath) were delivered on 19 December 1991, just before Chris Green left NSE to join the InterCity sector.

[27] Rail enthusiasts, staff and the general public gave nicknames to several types of rolling stock based on their appearance or characteristics.

The single-coach Class 121 units used on routes out of Paddington and Marylebone were known as "Bubble cars"—a name which has become official since the current operator Chiltern Railways obtained and refurbished one to work on services between Princes Risborough and Aylesbury.

[31] Rolling stock of all ages and types was painted in Network SouthEast's livery, made up of horizontal stripes of its house colours of red, white, blue and grey.

[15] "Bright", "brash" and "garish" in contrast to British Rail's sober dark blues and greys, it was nicknamed the "toothpaste" livery.

Network SouthEast inherited a large fleet of Class 421 ( 4CIG ) electric multiple unit trains dating from the 1960s.
Network SouthEast inherited more than 7,000 vehicles, many "drab" and ageing. This Class 416 unit in British Rail blue and grey livery stands at Tattenham Corner in spring 1984.
NSE refreshed train interiors (Class 421 vehicle pictured) with blue patterned seating, pale plastic panelling and strip lighting.
The "Networker" family included Class 365 (pictured) , 165, 166, 465 and 466 units, all manufactured in the early 1990s.
NSE's striped livery was likened to toothpaste.