Following the ending of production at AEC Southall, and the later closure of the Aldenham Works, new options for extending the life of the Routemaster became necessary if they were to continue to run.
This made sense as, even by 1987, when some buses looked decidedly worn out, inspections by London Buses revealed the basic structure of the buses was still sound, requiring only replacement of engines and interior/exterior renewal.

From 1992 to 1994, all but two of the RMLs were refurbished for ten years' further service.
This work, which included updating the interior to modern tastes and substituting Cummins or Iveco engines, was carried out by Mainline, TB Precision, Nottingham Truck & Bus and by one of the new London Buses business units, Leaside Buses.
One hundred RMs were also re-engined.
Post-privatisation, in 1996, London Central's RMs on route 36, Stagecoach London's RMLs for routes 8 and 15, and Arriva London's RMs for route 159 received new Scania engines and a number of subtle reworks including hopper style windows.

In 2001/02, under new Mayor of London Ken Livingstone, Transport for London purchased 50 RMs from a variety of sources, including Reading Mainline and two from Italy.
Of these, 43 were refurbished by Marshall Bus between May 2001 and August 2002, receiving Cummins engines coupled to an Allison automatic gearbox.
They also received a full body overhaul including new hopper windows.
The first 22 were leased to London Sovereign for use on route 13 with ten going to Arriva London for use on route 38 and others to First London, London Central and London United.
After Marshall Bus went into administration, Arriva London completed a further six, albeit without the heavy body overhauls and retaining the quarter-drop windows.
Following the ending of production at AEC Southall, and the later closure of the Aldenham Works, new options for extending the life of the Routemaster became necessary if they were to continue to run. This made sense as, even by 1987, when some buses looked decidedly worn out, inspections by London Buses revealed the basic structure of the buses was still sound, requiring only replacement of engines and interior/exterior renewal.
From 1992 to 1994, all but two of the RMLs were refurbished for ten years' further service. This work, which included updating the interior to modern tastes and substituting Cummins or Iveco engines, was carried out by Mainline, TB Precision, Nottingham Truck & Bus and by one of the new London Buses business units, Leaside Buses. One hundred RMs were also re-engined. Post-privatisation, in 1996, London Central's RMs on route 36, Stagecoach London's RMLs for routes 8 and 15, and Arriva London's RMs for route 159 received new Scania engines and a number of subtle reworks including hopper style windows.
In 2001/02, under new Mayor of London Ken Livingstone, Transport for London purchased 50 RMs from a variety of sources, including Reading Mainline and two from Italy. Of these, 43 were refurbished by Marshall Bus between May 2001 and August 2002, receiving Cummins engines coupled to an Allison automatic gearbox. They also received a full body overhaul including new hopper windows. The first 22 were leased to London Sovereign for use on route 13 with ten going to Arriva London for use on route 38 and others to First London, London Central and London United. After Marshall Bus went into administration, Arriva London completed a further six, albeit without the heavy body overhauls and retaining the quarter-drop windows.
AEC Routemaster