Suburban Electric Railway Association      
Located at the COVENTRY ELECTRIC RAILWAY CENTRE, Rowley Road, Baginton, Warwickshire           


Established 1996


Who Are We?

The Coventry Site

Latest News

Current list of items in our collection

What are we working on ?

Membership Of SERA

Can you help us out ?

Our Contact Details

Links to other sites of interest

Please Take Part In Our Visitor Survey






  4-SUB Units - Principle Data

Number Of Coaches Per Unit  Four
Formation Of Coaches Driving Motor Coach-Trailer-Trailer-Driving Motor Coach
Motor Equipment Two250hp motors on bogies at each driving end (1000hp total)
Coach Lengths 63 foot 6 inches each coach (excluding buffers)
Coach Weights 46 ton 10 cwt (Driving Motor) - 32 ton 12 cwt (Trailer)

So Why Preserve One Of These ?

The SUB units were the link between when the Southern Railway workshops stopped building EMUs that were basically motorised versions of their steam hauled coaches and produced something that was engineered for the electric commuter service they were providing. Designed with doors to each bay of open saloons with crush loading in mind rather than passenger comfort. This style paved the way for the British Railways Mk. 1 suburbans that followed and a design that evolved right the way through to the VEP units of the early 1970s. This unit epitomises 50 years of the typical everyday commute to and from London from south of the Thames.

History Of The 4-SUB Units
1941 - 1983

Official photo of the first production SUB, unit number 4111

Photo: SERA Archives

The 4-SUB units were designed both as replacements for the first generation of suburban units introduced by the London & South Western Railway (1915) and the Southern Railway (1925) as well as to provide stock for increases in passenger demand on the Southern suburban network.

The units were designed by the Southern Railway under the direction of that company's Chief Mechanical Engineer Mr. Oliver Bulleid. The units were at first envisaged to be a combination of long established Southern carriage building and electric traction tradition coupled with a few new ideas on body construction and styling.

The first unit emerged in 1941 and like all subsequent units of this type had four coaches, the outer two had driving cabs and carried traction equipment as well as accommodation for 108 passengers in nine compartments with six a side seating. The extra seats (previous stock only offered five a side compartments) had been obtained by using a curved profile to the bodyside which gave precious extra inches enough for one more person - at a squeeze !!!! The intermediate trailer cars had ten and eleven compartments with a total passenger accommodation for 456 in all four coaches. The vehicle bodies sat on a traditional Southern Railway suburban underframe but the bodies featured all steel construction as opposed to the timber as had previously bee the Southern preferred choice of coach building material. The roof was made of timber slats covered in canvas as per previous coach tradition. A further nine units were built to this initial 4-SUB design in 1944/45 and had a few differences to the prototype, their seating capacity was raised to 468. The first ten of the 4-SUB fleet were numbered 4101-4110 and became known as 'Shebas'.

Full production of 4-SUB units began in 1946 at Eastleigh works, the units were built on underframes that had either been built new at Lancing Works or second hand frames from older units that were reconditioned at Lancing. The first production unit numbered 4111 featured a couple of major differences from the Sheba design; the compartments were more spacious due to sacrificing one compartment from each coach to provide more room for standing passengers (a common occurrence during peak times) and also the carriage roof was, like the body, made of steel. During 1946 and 1947 further units were constructed to this style but many different layouts of seating were tried until it was decided to settle on the arrangement used first on unit 4277 of two eight bay saloon layout motor cars, one ten bay saloon trailer and a ten compartment trailer. This layout Provided for 386 passengers on each of the 257 foot long four car units.

Production of 4-SUB units ran from 1941 to 1951 and a total of 185 units were built. Their duties were as suburban units on the commuter networks that radiated out from the London termini of Waterloo, Victoria, London Bridge, Charing Cross, Holborn Viaduct and Cannon Street to the suburbs in South, South-West, South-East London and parts of Kent, Surrey, Middlesex and Berkshire. Destinations as diverse as Dartford and Windsor. Occasionally they may have been called upon for special trips further afield to coastal destinations but as a rule they never strayed much from the suburban networks.

Withdrawal of the type began in ernest in the late seventies and continued through the early eighties. The last SUB unit ran in passenger service on British Rail on the 6th of September 1983 with a commuter service into Victoria from East Croydon.

One unit was retained for the next 11 years for special duties such as enthusiasts charters and open day shuttles. Numbered 4732 it had been the last unit to receive classified repair in 1982 and to mark this event it was repainted into Southern Railway style green livery. The unit was stored from 1995 onward and became the target of several preservation attempts. The scheme sponsored by SERA was the only one that met with success.


A typical scene on a southern suburban line in the 1950's and 60's with
an all over green 4-SUB unit leading two older 2 car EMUs past a
row of back gardens on a service from London.

Photo: SERA Archives


Blue liveried 4-SUB unit 4658 brings up the rear of a Waterloo bound
service at it leaves Clapham Junction in the summer of 1982.

Photo: SERA Archives


Preserved 4-SUB unit 4732 pictured at the Coventry Railway Centre
in June 1999 shortly after being delivered to the site.

Photo: Graeme Gleaves

Did You Know.........

This unit is made up of vehicles from three different SUB units. The driving motor coaches are from the original 4732 but both the trailers were swapped at various stages in the units history for other vehicles when the originals trailer cars were damaged in collisions in depots.



BACK TO OUR FLEET PAGE