The first batch of locomotives were sent to East Anglia. Between 1968 and 1976 about two thirds of the fleet were modified with the addition of air brakes. Until the programme of dual braking was complete, BR had to be careful about which locomotives to operate on air brake only trains.

In 1985, a major refurbishment programme for the Class 37 locomotives started, and 135 locos were modified, leaving 173 unrefurbished locos. Features of the refurbishment was the sealing off of the nose end communication doors and plating over of the four character headcode boxes.

Alternatives to a complete major refurbishment for the Class 37/0 fleet were considered as the refurbishment of the whole fleet was considered too expensive. Conseqently a small batch of locos were given a standard intermediate overhaul, and were fitted with CP7 bogies recovered from withdrawn Deltics. These locomotives were reclassified  in the 373xx series. These locos were used in a common user pool with the rest of the fleet on mixed traffic workings during the transition from BR to EWS until final displacement and withdrawal by the new EWS Class 66s.

Current Status

There are no locos in mainline traffic from this subclass. A handful exist in preservation.

As electric train heating was phased in to replace steam heating, a batch of 31 Class 37/0 locomotives underwent full refurbishment in 1985/1986 at Crewe Works. This refurbishment was in conjunction with the fitting of ETS supply and replacement of the main generator with a main alternator. In addition, a full rewire was carried out. These modifications enabled the locomotives to work passenger trains both in the winter and the summer, with the fleet being split between Wales and Scotland. The ETS fitted subclass were allocated the 374xx number sequence, following other classes in having the ETS fitted locos designated as xx/4's. The splitting up of the trainload companies saw the entire 37/4 subclass allocated to Transrail, then passing to English Welsh and Scottish Railway.

Once widespread, work for these versatile locos included locomotive hauled trains over the Far North lines in Scotland between Edinburgh and Fort William/Oban/Inverness, services in South Wales and the Western Region along with the majority of services on the North Wales Coast Line between Holyhead, Crewe and Birmingham.

Seen as expensive and operationally inefficient, loco haulage declined as replacement by Diesel Multiple Units beckoned on most services. With the large builds of new stock at privatisation, cascade programmes were put into place which virtually eliminated the conventional use of locomotives and coaches. Affected by the arrival of Class 66s to a lesser extent due to their valuable ETS capacity, the fleet was nonetheless still reduced as passenger requirements decreased. Removal from the North Wales Coast and the Western region was achieved early on in the privatisation process, while, notably, the Rhymney Valley in South Wales bucked the trend by gaining services operated by 37/4s to cope with increased in demand during the peak travel hours.

Current Status

At the time of writing, only 4 examples are left in active, everyday service - forming the entire EWS Class 37 fleet. The fleet has two booked diagrams on paper, but in reality these are often substituted with any other class of loco that is available.

The remaining stored fleet of 37/4 locos is still entirely owned by EWS (with the exception of preserved 37414) and are still showing a reluctance to sell these popular and versatile locos, which can only be a testament to their continued suitability to secondary passenger duties.

During the 1980s major refurbishment programme for the class, a batch of Class 37/0 locos were refurbished in the same manner as the Class 37/4s with a full rewire, major overhaul and fitting of CP7 bogies but they were not fitted with ETS equipment. This was to give a subclass of locos specifically dedicated to freight work; something never done before as the original fleet of 37/0s were intended as a mixed traffic design - something which became reality.

Two batches of locos were completed - from phase 1 and phase 2 of the original 37/0 build series; distinguishable by the presence of central headcode boxes (phase 2 build) or split boxes (phase 1). Two number series' are allocated as a result of this difference with the phase 1 locos taking 37503-37521 and having a flush front end (as shown on 37517 below) with phase 2 taking 37667-698 and having central headcode boxes - albeit plated over.

Current Duties

Again, the EWS locos were affected by the arrival of the Class 66s with no locomotives in traffic as of early 2005. However there is one modification the majority of the class has which does make them valuable to EWs; they are fitted with sandite laying equipment which sees members of this subclass reactivated in the autumn of each year for hire to Network Rail.

DRS currently has one member of this subclass in traffic - one of the batch it bought from Harry Needle Railroad Co in 2005. This loco - 37515 - is used with the rest of the fleet.

During 1995/1996, twelve Class 37/5 locomotives were refurbished and ETH through wired for use with generator cars for hauling the proposed 'Nightstar' services on non-electrified routes through Britain (Plymouth/Exeter). The refurbishment was carried out at Doncaster Works, and it also included removal of the vacuum braking system. RCH jumper cables were also fitted to enable the locomotives to work in multiple.  

As it became clear that the 'Nightstar' services were unlikely to ever run, in June 1997, Eurostar UK (EUK) initially sold half of the fleet of 12 locomotives to Direct Rail Services, followed by a further three locomotives three years later bringing the DRS total to 9 Class 37/6 locos.

Current Duties

Three Class 37/6 locos are still in the EUK fleet are used for hauling Eurostar units over non-electrified lines, or rescuing them in the event of a failure in service. Work for these three locos has reduced in the past few years with the Eurostar units becoming more reliable and being passed for more electrified routes in the UK. The locos have also been used for driver training and route learning in recent times.

The DRS locomotives are seen as part of the 'core' fleet along with the Class 66s, although they commonly work alongside its fleet of Class 20 locomotives on nuclear flask trains around the country. Appearances on intermodal trains were also common until replacement by Class 66s, although re-appearances are not unheard of, deputising for failed locos.

Again, as part of the major refurbishment scheme in the 1980s, another freight dedicated fleet of 44 Class 37s was created; the Class 37/7 subclass which was identical to the 37/5 subclass except for the addition of a ballast weight to give extra 'pulling power' when hauling heavy freight trains such as the metals trains in South Wales. Again, like the 37/5s, there were two batches completed; from phase 1 and phase 2 Class 37/0 locos. The batch numbered 37701 downwards were from phase 1 build locos and have the flush front ends and the batch numbered from 37899 upwards were rebuilds from phase 2 locos, having the central headcode box (plated over). A further complication exists; locos numbered 37796-37803 had a different type of electrical equipment fitted as part of a trial and differ from the other locos in the subclass internally.

This subclass, being freight only, was decimated by the introduction of newer Class 66s directly replacing them and also through displacing other traction to replace the locos. The fact that the locos are heavier than standard Class 37s meant that, despite having been refurbished, they were not retained for operating trains over lines on which heavier locos were banned. Large numbers of this fleet are in 'warm storage' for reactivation during the sandite season and a number of locos were reactivated or transferred from the active fleet in 2001 for a hire contract in Spain from which they have yet to return.

Current Duties

This subclass has no active examples in the UK; owned by EWS and attractive to competitors, loco sales are few and far between and those locos which have been sold on are only fit for use as spares. 11 locos are still active in Spain on hire to GIF and Continental Rail.

The refurbishment programme for the Class 37 fleet concluded in 1987 when options for replacement of the fleet was looked at by BR. As an alternative to complete replacement, a final subclass of 6 locomotives were given a heavy overhaul (as with the rest of the fleet) and re-equipped with new power units to gauge performance and thus suitability for future use. Two units were chosen, one from Mirlees (fitted to 37901-37904) and one from Ruston (fitted to 37905 and 37906). The locos formed a non-standard subclass within the fleet and were allocated to Cardiff Canton in Wales, working on the heaviest freight trains in the country with some of the steepest gradients. Trials were successful although with privatisation looming, no further work was done and the 6 locos continued to work in Wales. Of note is that the Mirlees power unit (as fitted to 37901 to 37904) was chosen to become the prime mover for the new build of Class 60 heavy freight locomotives.

The subclass was non-standard right from the start and following completion of the trials, they became dispensable and any major fault would see locomotives awaiting repair for months on end. The takeover of Trainload Freight by EWS and subsequent upsurge in freight traffic saw all available motive power reactivated, this included the 5 serviceable Class 37/9 locos which were once again allocated to Cardiff Canton depot. Class 66 deliveries saw them replaced for one last time with storage following.

Current Status

Just four out of the original six locomotives are still in existance and all but one are in stored status at various places around the country: 37901 is preserved and awaiting completion of engine repairs at the Llangollen Railway in Wales, 37902 has been scrapped after its overhaul by Direct Rail Services was aborted, 37903 is owned by Harry Needle Railroad Co and stored in a heavily stripped state at Crewe DMD, 37904 was used as a spares donor for 37901 and has now been scrapped, 37905 is still owned by EWS and stored at Immingham depot and finally 37906 which was restored for the Old Oak Common open day in 2000 has been stored at the Severn Valley Railway by EWS for 4 years following an alleged disagreement between the two parties.

Last Updated 17-08-2006