Locos in BR Blue TOPS Era

By Andy Joel

This is an article about British Rail from about 1972 to about 1985, often referred to by modellers as era 7. It gives a brief overview of the locos running on British Rail at that time, and is written to support the articles on freight and coaching stock to help the modeller build a realistic train, rather than being a comprehensive record of locos at that time. If you see any errors or have suggestions or further information, do please let my know.


TOPS (Train Operating Processing System) was a computer system for tracking locos and rolling stock, introduced in 1973. Under the system all locos were re-numbered; given a five digit number, the first two usually written separately, and denoting the loco class. The third digit often denotes the sub-class. Thus 47 401 is a class 47 loco, or more specifically a 47/4.

Prior to 1973 locos were numbered according to the order they were built (kind of – they were batched together, so locos in a class form a sequence), and originally were prefixed with a “D” for diesel and “E” for electric. Class 47 locos, for example, were originally numbered D1100–D1111 and D1500–D1999. When locos were renumbered for TOPS, the last two digits were usually kept the same where possible.

The class of a loco, pre-TOPS, was described by its type and its manufacturer. The type was determined by its power rating. Type 1 was 800 to 1000 hp, type 2 was 1001 to 1499, type 3 was 1500-1999 hp, type 4 was 2000-2999 hp and type 5 was over 3000 hp. A class 47 would have been know as a “Brush type 4”. This does leave me wondering how the class 24 and 25, for example, were differentiated, as both are Sulzer type 2…

Background History

Between 1958 and 1962 British Railways introduced a large range of diesel and electric locos, designed to replace steam. The mainline diesels were classes 16, 17, 20, 21, 22, 23, 24, 25, 26, 27, 28, 33, 35, 37, 40, 41, 42, 43, 44, 45, 46, 47, 52, 53 and 55 (classes 29 and 31 were later rebuilds from earlier classes). There were also two classes of DC electric loco, 71 and 73; and five of AC electric loco, 81, 82, 83, 84 and 85. After introducing 30 new locos in just fives years, from 1963 onwards, the introduction of a new class of loco was a rare occurrence.

Many experienced issues and failures, and part of the reason for that is that they were working a long side dirty steam locos, and also that the staff were not that familiar with how to handle and maintain them. Nevertheless, many were less than successful.

By 1968, the last mainline steam locos had been with drawn (the only exceptions being on the Vale of Rheidol; London Transport kept steam for departmental use until 1971). Not long after steam had disappeared, many of those early classes of diesels did too.

Earlier locos had to be built to work with existing rolling stock, and that meant vacuum braking and, for passenger trains, steam heating, because these were the systems that worked best for steam locos. The steam heating on diesel locos was a major cause of faults; it was also heavy and took up a lot of space.

An exception was the class 33, with electric train heating (ETH) and no steam heating when built, as it was designed to work with the EMUs running on the Southern Region. The class 33 is essentially a class 26 with a larger engine using the space the steam heating system used on the class 26.

Once steam had gone, air braking and ETH became more common. Many locos were converted to be able to handle both, and later still steam heating and vacuum brakes might be removed altogether (though generally later than this era, I think).

All this leaves the modeller wondering: what loco can I run with my rake of coaches or wagons?

Classes that were withdrawn by 1972 I do not bother to say anything about. You can be sure all had vacuum brakes, not air brakes. If they had train heating, it will he steam, not ETH (type 1 locos may not have had any).

This is just a brief overview. For more details, a good starting place is Wikipedia, which has a page for every class of diesel and electric loco.

Livery Variations

The last loco in green livery was 40 106, which actually got repainted green during the blue era, in 1978, I think because it was by then the last loco (or mainline loco) in green. 47256 was still in two-tone green in 1977, and there is some suggestion some class 20s and 47s from Toton were still green around this time, though the photographic evidence is not great, and to me looks like weathered blue. There are suggestions the Liverpool Street Station pilot, a class 08, may also have had a green repaint. There is an interesting discusson here.

In 1976 the HST entered service. While it sported the normal blue, yellow and grey colours, the arrangement was very much non-standard, perhaps due the the stream-lining not lending itself to the usual full yellow ends. The HST livery never appeared on any other locos.

In 1977 a couple of class 47s (47 163 and 47 164) were painted with silver roofs and huge union flags painted on the sides to celebrate the Queen’s silver Jubilee by Stratford depot. The depot subsequently did the roofs of a number of 47s in a similar manner, but with grey (possibly the same grey as used on coached), rather than silver paint.

From 1979, the “large logo” livery officially started to appear, initially on new class 56s, later on refurbished class 50s as they moved to the Western Region. I think a handful of 47s received it in an unofficial way even earlier – an extension of the Stratford silver roofs, but also on some Scottish class 47s too. It became quite common on class 47s and class 73s too. At least some 37s, plus 25 322, 33 012 and 87 006 also received the livery (in some form) at some point, but was not all that consistent. The livery features large numbers and an all-over yellow cab with black window surrounds, and there were examples of locos with one, two or all three of these features in the early eighties. There was also often a regional symbol added, such as a highland terrier for locos based at Inverness. Later examples for the freight sector were painted grey, rather than blue.

From 1983, a new Inter City livery started to appear, with dark grey above light grey, separated by red and white stripes, having previously been seen on the experimental APT. This takes us out of the BR Blue era.

Headcodes and Discs

Locos built from 1960 were fitted with boxes at each end to display the train headcode. This is more technically called the train reporting number, and had already been in use for some years, without being displayed (except on specials and non-routine trains). 

Prior to 1960, locos were built with four white discs on each end following steam practice. The top half of each disc could be folded down to hide it, also covering the light; different combinations indicated the train type. I find it odd that these locos were not layer fitted with headcode boxes to bring them in line with later locos.

The codes consist or four characters; a number indicating the class of the train (and so indicating its speed), a letter indicating its destination, and two further numbers indicating the individual route or service.

From the start of 1976 their use on locos was abandoned, as signalling improved and it was no longer necessary for signalman to be able to see them, though they are still in use behind the scenes to this day. At first – and pretty much overnight I think – they were all set to 0O00, but were later replaced, at least in some cases, with two white circles on black fairly quickly. I think some multiple units, such as class 310, had three dots at the first class end (example here). Some locos had the box plated over (class 86s for example). By the early eighties locos were appearing with headcode panels removed altogether.

The Southern Region, following practice from the Southern Railway, had a two digit headcode displayed (and this really is the “headcode”). There are some comprehensive lists here.

Diesel Locos

Class 14: Only introduced in 1964, they were all withdrawn by 1968 – though many went on to have long lives in industrial ownership.

Class 15 (BTH Type 1): All withdrawn by 1971

Class 16 (NBL Type 1): All withdrawn by 1969

Class 17 (Clayton Type 1): All withdrawn by 1971

Class 20 (English Electric Type 1): Some of these are still running today! They had no train heating fitted, though a few had a through pipe to allow them to work with class 27 on the West Highland Line, and some were used on passenger trains during the summer (particularly to Skegness!) when train heating was not required. I think they were originally vacuum braked, but some or all were later converted to dual braked. The big question is, when?

Class 21 (NBL Type 2): All withdrawn by 1971, or rebuilt as class 29

Class 22 (NBL Type 2 Diesel-Hydraulic): All withdrawn by 1972

Class 23 (English Electric Type 2): All withdrawn by 1971

Class 24 (Sulzer Type 2): Last withdrawn in 1980. Fitted with steam heating as built, but some (many?) had it later removed. Ten locomotives (D5102–5111) had no train heating, the space being occupied by the air compressors needed for operation of the Consett iron ore trains

Class 25 (Sulzer Type 2): Last withdrawn in 1987. Some had steam heating, I think as built, no sign any had ETH.

Class 26 (BRCW Type 2): Last withdrawn in 1993, these spent virtually all their working life in Scotland. Given they were used on passenger trains originally, but less so by the eighties it seems likely they had steam heating, but no ETH.


Class 27 (BRCW Type 2): Last withdrawn in 1987, like the class 26 they resemble, they were based in Scotland (exclusively from 1969). Some were converted to 27/1 and 27/2 in the early seventies, both sub-classes were dual braked, 27/2 was ETH fitted. This was mainly for the Glasgow to Edinburgh service, with a 27/1 on one end and a 27/2 on the other. The service was taken over by a class 47 in 1980, and the class 27 locos renumbered in 1982 back to 27/0. It is not clear if they were converted back as well.

Class 28 (Metropolitan Vickers Type 2): All withdrawn by 1968

Class 29: All withdrawn by 1971.

Class 31 (Brush Type 2): Last withdrawn in 2017; there were a number of sub-types. 31/0 were the first batch; they had no headcode box, and were all with drawn by the late seventies as non-standard. 31/1 was the standard version, while 31/4 was for locos converted from 31/1 with ETH fitted. Seems likely they all had steam heating, but yet to confirm that.

Class 33 (BRCW Type 3): Are some still in use? As mentioned, these had ETH fitted from build, but no steam heating. I suspect they were dual braked from build too, as again EMUs were often air braked.

Class 35: Last withdrawn in 1975. Based exclusively in the western region, they had steam heating and vacuum braking.

Class 37 (English Electric Type 3): Some of these are still running today! Part of its success is its relatively low axle weight for its power. Members of the 37/4 sub-class have ETH fitted, but this was only done in 1985-6 (often with large logo repaint).

Class 40 (English Electric Type 4): Last withdrawn in 1985, their hey day was the early sixties when they hauled the expresses on the WCML, until replaced by class 50 locos. Thereafter they were based in the north of England and Scotland. One loco was trialed with ETH, but otherwise they had only steam heating. Many were never fitted with air brakes.

Class 41: All withdrawn by 1967.

Class 42: All withdrawn by 1971.

Class 43: All withdrawn by 1971.

Class 44 (Derby Type 4): Last withdrawn in 1980, and based in the East Midlands prior to that. Fitted with steam heating and vacuum brakes.

Class 45 (Derby Type 4): Last withdrawn in 1989, and based in the Midlands Main Line prior to that. Fitted with steam heating and vacuum brakes. 45/1 had ETH; I guess a later conversion. They had air brakes; again, I guess a later conversion.

Class 46 (Derby Type 4): Last withdrawn in 1984, and based in the Midlands Main Line prior to that. Fitted with steam heating and vacuum brakes. 45/1 had ETH; I guess a later conversion. They had air brakes; again, I guess a later conversion. Looks like they only had steam heating and vacuum brakes.

Class 47 (Brush Type 4): Some of these are still running today! Simplistically, 47/0 had steam heating, as originally built; 47/3 were 47/0 with the steam heating removed; while 47/4 were 47/0 with ETH fitted (and steam heating removed in some cases). All 47/3 and some 47/0 had slow speed control for MGR trains. 47/7 were conversions made in 1980 for push-pull service between Glasgow and Edinburgh (so would have ETH and air brakes, and almost certainly the steam heating taken out to allow for long range fuel tanks).

Class 48 (Brush Type 4): Class 47 locos with a different engine. They were not reliable and all were converted to 47 by 1971 (became 47 114-47 118).

Class 50: Introduced in 1967, last withdrawn in 1994, these were built for the WCML, replacing the class 40 locos, working north from Crewe (south of there being electrified). By 1974 the whole WCML was electrified, and the locos were transferred to the Western Region, to replace the class 52. Being a relatively recent class, it was dual braked and ETH fitted from build.

Class 52: Last withdrawn in 1977. Based exclusively in the western region, and later in life in more specifically in Laira, Plymouth. They had steam heating and vacuum braking, and from the later sixties they also had air brakes (except for four!). It was not possible to equip them with ETH.

Class 53: A single prototype, withdrawn in 1975. Steam heating and vacuum braking, with air brakes fitted later.

Class 55: Last withdrawn in 1982. The class 55, or “Deltic” was designed to haul trains on the ECML, until replaced by HSTs in 1978. They were vacuum braked and had steam heating from build, had air brakes fitted in the late sixies, and ETH in the early seventies.

Class 56: First built in 1976, these are still in use. They were built for freight, so have no train heating and all are fitted with slow train control for MGR trains. They have air brakes only.

Class 58: First built in 1982, last withdrawn 2002. They were built for freight, so have no train heating. They have air brakes only. They were delivered in Railfrieght grey livery.

Third Rail DC Electric

All these ran exclusively on the Southern Region, though the class 73 has wondered much further a field in recent years.

Class 70: Three prototype locos, all withdrawn by 1971. Steam heating; vacuum, air and electro-pneumatic brakes.

Class 71: Last withdrawn in 1977, but some members were converted to class 74. ETH; vacuum and air brakes.

Class 73: Some of these are still running today! ETH; vacuum, air and electro-pneumatic brakes.

Class 74: Converted from class 71 in 1968, last withdrawn in 1977. ETH; vacuum, air and electro-pneumatic brakes.

Overhead DC Electric

All these ran exclusively on the Woodhead route from Manchester to Sheffield

Class 76: Built in 1950 to a design by Sir Nigel Gresley, the last was withdrawn in 1981, when the Woodhead line was closed. Fourteen had steam heating, the rest no train heating. They were vacuum braked with some later air braked too.

Class 77: Built in 1953 as a development of the class 76, they were all withdrawn in 1968 and sold to the Netherlands railway the following year (finally withdrawn in 1985). Steam train heating and vacuum brakes.

AC Electric

All these ran more-or-less exclusively on the WCML, with occasional visits to the lines out of Liverpool Street.

Class 81: Last withdrawn in 1991. ETH; vacuum braked when built, air brakes added 1972-73.

Class 82: Last withdrawn in 1987. ETH; vacuum braked when built, air brakes added 1971-72.

Class 83: Last withdrawn in 1989. ETH; vacuum braked when built, air brakes added 1972-73.

Class 84: Last withdrawn in 1980. ETH; vacuum braked when built, air brakes added 1972.

Class 85: Last withdrawn in 1992. ETH; vacuum braked when built, air brakes added 1968-71.

Class 86: First introduced in 1965, and still running. ETH; vacuum and air braked when built.

Class 87: First introduced in 1973, last withdrawn in 2006 (most were then exported to Bulgaria). ETH; air braked only when built.

Class 89: First introduced in 1986, this single prototype was withdrawn in 1992 after a serious failure, later re-built and re-introduced in 1997, to fail again in 2001. ETH; air braked only when built. NOTE: This class designation has also been used for several dozen preserved locos since 1989.

Class 90: First introduced in 1987, and still running. ETH; air braked only when built. None appeared in BR Blue.