The units were converted from Class 414 driving motors cars, by Eastleigh Works in 1983-84, for use on the new Gatwick Express service.

However, purely for aesthetic purposes, only the last four digits of the set numbers were shown, to fit with the traditional Southern style (maintained until privatisation by British Rail's Southern region) - older (pre-TOPS) units were originally assigned four-digit numbers.

Immediately after privatisation, the Class 489 fleet was exclusively used by Gatwick Express on all their London Victoria-Gatwick Airport shuttles.

Two of the units were donated by Porterbrook Leasing in 2003 to the Ecclesbourne Valley Railway in Derbyshire, which now uses one as a buffet car and the other a museum.

Another unit, 489108, was bought by a private owner for preservation at Nottingham Transport Heritage Centre, but it was sent for scrap in May 2009.