Diesel and Electric Locomotives on BR/Railtrack

This page gives a very brief description of each diesel or electric locomotive class to have operated on the mainline railways of Britain.

In the tables below, only a single number range (lowest numbered to highest numbered locomotive) is given, even though many classes were not numbered in a single continuous series. An asterisk * indicates that a number range also included locomotives of other types. Also, the TOPS number range given in the first table is that of initial TOPS numbers; subsequent renumberings may have taken the series beyond the range shown. (TOPS numbers are the ones used in Britain since the early 1970s, and are named after the computer system for which they were introduced.)

Power ratings should be taken as approximate. Different sources often quote different power ratings (sometimes there are as many as four!) for the same locomotive type. This may be due to a number of reasons; sometimes a class had its engines uprated or derated during its life, sometimes different locomotives within a class had different engine ratings. Of course it is also possible that some of the discrepancies are due to errors.

The figures (i) and (ii) indicate the first and second uses of a class number which has been re-used, whilst (a) and (b) refer to simultaneous use of the same class for two different groups of locos.

Table of Classes

Sub-Classes

Some classes are divided into sub-classes to denote important variations within a class. These are shown in the following table. As in the above table of classes, (i) and (ii) refer to re-use of a sub-class, whilst (a) and (b) refer to simultaneous use of the same sub-class for two slightly different groups of locos. It should be noted that enthusiasts often refer to some fictitious sub-classes based on number ranges, even though these do not officially exist. Common examples are "31/5", "47/8", "47/9" (referring to 47971-47981) and "97/8".

Where a blank is shown under "description", this is considered the "standard" locomotive without special features or modifications. Generally this is sub-class /0, but in the case of Class 31 the 31/0s are considered non-standard and the 31/1s standard.

Where an asterisk is shown under "description", this is the "standard" locomotive and originally included the entire class. In such cases, reference to the sub-class /0 only came about when other locomotives in the class received modifications (or in the cases of Classes 09 and 57, were transferred from another class).

Where a + symbol appears by a number, it indicates that there definitely are (or were) this many, but I don't know if there were (or will be) more.

Where differences are as a result of modifications, a blank is generally left for the number of unmodified locos to avoid any possible confusion over what the number refers to.

Page by Dave Root (dave@quackduck.org.uk) - December 2001
Thanks to Rob Volland for additions and corrections.