Post-privatisation
During the 1990s, the few remaining Mark 1 loco-hauled vehicles on the main line were withdrawn, having been progressively replaced by Mark 2 and Mark 3 stock through the 1970s and 1980s. However, the extensive South London commuter network in the former Southern Region was worked mainly by Mark 1 based multiple units - a situation which would be a major focus for improvement as the prospect of privatisation dawned in the 1990s.
When privatisation took place, after 1994, only Connex South Eastern was given an extended franchise (15 years) in return for ordering new trains. Connex South Central and South West Trains, the other major users of Mark 1 multiple units by that time, were not expected to order new trains. As a result, in 2000, Mark 1 units were still in use across most of the former Southern Region with no new trains having been ordered.
Events then moved rapidly. The three southern franchises ordered hundreds of new multiple units of classes 171, 375, 376, 377, 444 and 450 to replace the remaining Mark 1 stock.
A similar story took place in Glasgow, with the last of ScotRail's venerable Mark 1 based Class 303 multiple units surviving until the end of 2002, when Class 334 replaced them on all Glasgow commuter lines.
The use of Mark 1 stock on postal trains was curtailed when the Royal Mail partially replaced them in the early 1990s. The flagship postal train services on the West Coast Main Line was worked using new Class 325 multiple units based on the "Networker" design. However, these units proved to be extremely troublesome in service and due to technical failures were often loco-hauled instead of running under their own power, and therefore Mark 1 formations continued to be used here, and elsewhere on the network. However, in the early 2000s, the Royal Mail decided to cease the use of rail to transport mail traffic. Thus, the problem of how to replace the large numbers of Mark 1 carriages on these services was answered. However, in 2005, EWS resumed some mail services using the Class 325 stock.
Network Rail and its associated infrastructure companies continue to use converted Mark 1 coaches for various departmental duties – test trains, sandite units, and accommodation units for worksite personnel are some examples.
A small number of railtour companies have waivers to operate Mark 1 coaching stock on railtour duties. The conditions usually involve the fitting of central door locking and having either a non-passenger or non Mark 1 coach at the ends of the train. This is often achieved by running with a locomotive at each end of the train, instead of just at the front, which also reduces the need to run-round at minor terminus stations, many of which lost their run-round facilities when locomotive hauled trains of Mk1 or Mk2 coaches gave way to multiple unit operation on service trains.
Read more about this topic: British Railways Mark 1