92212 Each
steam locomotive was allocated to a particular shed and an oval, cast metal plate (usually ) with the depot code was bolted to the smokebox on the front of the locomotive. When a locomotive was reallocated to a different shed the plate was taken off and replaced with one from the new shed. Locomotives moved between a parent depot and its sub-sheds did not need this change as they shared the same code. With the introduction of diesel and electric motive power the system of allocation became changed. Main line locomotives were capable of operating greater distances between servicing and, very often, depots only held the equipment and spare parts for servicing a limited range of locomotive classes. This resulted in them being allocated to a smaller number of depots and reallocations became less common. For instance, the 74
Western Region Class 52 diesel-hydraulics were only ever allocated to six depots and were eventually all based to just one (
Laira) rather than spread around more than 60 depots on the region, although they could often be found at many of these others. This meant that many depots only had allocations of shunting locomotives, and some locomotives did not carry allocation plates. Those that did had them in a variety of positions:
Class 42s on the underframe below the cab but near-identical
Class 43s on the front next to the left buffer; after 1967 the code was generally painted on the bodywork near the cab door. On the London Midland Region, from June 1968 until 1973 main line diesel locomotives were given a divisional allocation in which locomotives were allocated to a nominal district, although in practice the locomotives received major attention at the principal depot in the Division. For example, locomotives in the D01 London (Western) Division were effectively based at principal depot
Willesden. Other divisions were D02 Birmingham Division (
Tyseley), D05 Stoke-on-Trent Division (
Crewe), D08 Liverpool Division (
Allerton), D09 Manchester Division (
Longsight), D10 Preston Division (
Lostock Hall), D14 London (Midland) Division (
Cricklewood Depot), D16 Nottingham Division (
Toton). ==List of codes==