British Rail locomotive and multiple unit numbering and classification

A number of different numbering and classification schemes were used for locomotives and multiple units operated by British Railways (BR), and this page explains the principal systems. This section also covers the post-privatisation period, as the broad numbering and classification arrangements have not altered since the break-up of BR.

Locomotives and multiple units (the majority being self-propelled) have frequently had similar arrangements for classification and numbering, so are considered together here. There are also links to other pages that deal in greater depth with the particulars of individual types.

Constituent companies

In 1948, BR inherited a variety of locomotives and multiple units from the 'Big Four' railway companies and some smaller concerns. Details of the numbering and classification systems used by the 'Big Four' companies are covered in the following pages:
* Great Western Railway: GWR locomotive numbering and classification
* Southern Railway: SR locomotive numbering and classification and SR multiple unit numbering and classification
* London, Midland and Scottish Railway: LMS locomotive numbering and classification
* London and North Eastern Railway: LNER locomotive numbering and classification

In the main, new locomotives and multiple units built by BR to pre-nationalisation designs were numbered and classified according to the principles applied by the relevant 'Big Four' company.

1948 numbering and classification

Immediately after nationalisation, BR had to decide how to number and classify the stock it had inherited from the 'Big Four' companies, and how newly-built stock would be included. In the main, it decided to simply adapt what was already there.

Locomotives

The classification systems of the 'Big Four' were left unchanged for the inherited locomotives. However, BR decided to adopt the LMS power classification system as its preferred model and all inherited locomotives received a classification in this series as well as their traditional classification.

In order to remove the duplications of locomotive numbers, all locomotives were placed into a new number series as follows:

Of the shunters that were renumbered, the only transparent renumbering was for those that had been numbered in the 13xxx series, for which the '1' was simply replaced with a 'D'. All the others were completely renumbered to separate out the different classes.

As always, there were some oddities. The 650 hp diesel hydraulic locomotives later Class 14 were numbered from D9500 upwards. When the Type 2 series got too crowded later on, new Sulzer Type 2 locomotives (later British Rail Class 25) were numbered from D7500 upwards. Some experimental locomotives carried D0xxx numbers.

When the last mainline steam locomotive was withdrawn in August 1968 (leaving only three on the self-contained narrow gauge Vale of Rheidol Railway), the 'D' prefix was dropped.

Electric locomotives

The numbering system was divided into two series, one for AC locomotives and one for DC lomotives. DC locomotives were numbered from E5000 upwards, and DC electro-diesel locomotives, with a diesel generator for working off electrified lines, were numbered from E6000 upwards.

For AC locomotives, the first number was to be an indication of power. For example, if the power was in the range 2000 to 2999 hp, it would be numbered between E2000-E2999, and so on. In fact, apart from E2001 (the prototype AC locomotive, converted from a gas turbine locomotive, later Class 80), all AC locomotives were numbered from E3001 upwards. When new 5000 hp locomotives were under construction (later Class 87), these were allocated numbers from E3201 upwards, though they never carried these numbers as the 1973 arrangements were already in place by the time the first one was built.

1973 numbering and classification - TOPS

At the end of the 1960s, British Railways adopted the Total Operations Processing System (TOPS), a computerised system developed by the Southern Pacific Railroad in the United States. All types of locomotive and multiple unit received a TOPS classification, according to this broad division:

AC electric locomotive classes AL1 to AL6 became 81-86 in order.

Multiple units

The multiple unit series were divided up as follows:

Of course, many exceptions arose over time. One major change was to change the classification of unpowered trailer units from 49x numbers to 4x8 numbers (which involved reclassifying Class 491 to Class 438). When Southern Region unit numbers were changed to fit with the TOPS classification system, former 4x0 classes were all reclassified to 4x2. This was necessary because Southern Region units only displayed the last four digits of their six-digit TOPS number, and it was decided that no painted unit number should commence with a '0'. It is worth noting that despite only showing the last four digits, the actual number of the unit was still the six-digit TOPS number. This often causes confusion both to enthusiasts and those outside the field alike.

ee also

For further information on individual classes of locomotive or multiple unit, see these pages:
* List of British Rail classes
* Steam locomotives of British Railways
* Locomotives of the Great Western Railway
* Locomotives of the Southern Railway
* Locomotives of the London, Midland and Scottish Railway
* Locomotives of the London and North Eastern Railway

Related pages on BR numbering and classification include:
* British Rail TOPS first arrangement
* British Rail Regional Multiple Unit Numbering
* British Carriage and Wagon Numbering and Classification
* Route availability