Between 1864 and 1905 fifteen distinct classes and sub classes of 0-6-0
tank engines were built at Swindon and Wolverhampton, providing the Great Western
with over 1,100 light goods, shunting and branch passenger engines. The 5700 and
later 8750 class pannier tanks can trace their origins back to these saddle tanks
from the Armstrong and Dean era.
|A good proportion of these earlier saddle tanks were
converted to pannier tanks to prevent problems with injectors due to overheating
of the water in the saddle tank. The 57XX, although separated from them by 24
years, were an almost unaltered continuation of the saddle to pannier tank
conversions of the 27XX with a reversion to the spring arrangement and non-fluted
coupling rods of the previous
"1854" class of 1890. These in turn sprang from
the "1813" class of 1882 and the very similar Wolverhampton "645" class of 1872.
Remarkable not only for the length of their ancestry but also, once replacement
building started, for their numbers, which reached a total of 863 engines in
twenty years, they thus became the most prolific class on the G.W.R.
Their dimensions were:-
||Diam. 171/2", Stroke 24".
||Barrel 10' 3"
Diam. outs. 4' 5" and 4' 37/8".
Pitch 6' 113/4"
|Firebox||Length outs. 5' 4"
||No. 2, diam. 51/8"
No. 233, diam. 15/8"
||Tubes; 1075.7 sq. ft.
Firebox 102.3 sq. ft.
Total 1178.0 sq. ft.
|Grate area||15.3 sq. ft.
|Boiler pressure||200 lb.
|Wheelbase||7' 3" + 8' 3" total 15' 6"
||Leading 16t 15c
Driving 16t 15c
Trailing 14t 0c
Total 47t 10c
|Tank capacity||1200 gallons
|Coal capacity||3t 6cwt
|Height at top|
|By 1929 superheating, had been found of little value on shunting
engines, the two 51/8" superheater flues, being incerted
in the top corners of the firebox tubeplate to prevent cracking at these points.
The 200lb boiler pressure was higher than on the older engines and enclosed
cabs with enlarged bunkers were fitted from the start.
Externally the chief feature to distinguish them from
the older engines was the universal cast iron chimney. Of the first one hundred engines, fifty were built by the North British Locomotive
Co. Ltd., Nos. 5700-24 at the Hyde Park Works and Nos. 5725-49 at Queens Park.
Of the Swindon engines Nos. 5780-99, then Nos. 5768 & 70-8 had boilers on which the
steam supply to the fountain in the cab was taken from the dome in a covered pipe
along the tank top. This feature was discontinued, but the boilers found their way
to other engines before it was finally removed.
Nos. 5790-99 were built with Automatic
Train Control apparatus and the earlier engines were also equipped in the next
few years. Two hundred further engines were built in 1929-31, all by outside firms under a
Government scheme to alleviate the effects of the trade depression. These were -Nos.
6700-49, 7700-99 and 8700-49, of which Nos. 6700-49 had steam brakes only and
three-link couplings, but as there was little work for this batch most of them were
stored for a couple of years. The A.T.C. apparatus was put on Nos. 7750-99, 8700-49
on arrival at Swindon and on Nos. 7700-49 a few years after they were built. Nos.
5700-99, 7700-99 and 8700-49 were fitted up for vacuum brake but Nos. 5700-49
were built without steam heating apparatus although several subsequently acquired it.
Nos. 7700-25 / 75-99, 8700-49 arrived with polished brass safety valve covers, most
of which were soon painted over, although in later years many of the class had
again been brightened by the removal of the paint.
|For many years engines with condensing apparatus (0-6-OT's of the " 633 " class
and 2-4-OT's) had worked over the Metropolitan lines to Smithfield.
These older engines were now becoming due for replacement and No 8700 was
converted to a condensing engine in March, 1932. The tanks were cut back
at the smokebox end, the capacity being reduced to 1,080 gallons, and a vertical
feed pump fitted on the right side.
Branch pipes from the smokebox conveyed exhaust
steam to the centers of the tanks which were provided with steam vents.
The weights (full) became 17 tons 7cwt. + 17tons 7cwt. + 16tons, total 50tons 14cwt.
As a result of experience with this proto-type ten new engines, Nos. 9701-10, were
built at Swindon in the following year. On these the tank capacity was increased
to 1,230 gallons by forming the rear part of the tanks into side tanks and a much
improved form of cab with rounded roof, much larger windows and sliding shutters
adopted. Coal capacity was however reduced to 2tons 16cwt.
At the same time the boilers supplied had slight modifications (Class PJ).
No. 8700 was similarly modified and re numbered 9700 in January, 1934.
Nos. 9700-10 had special A.T.C. apparatus which was automatically clipped up clear
of the live rail upon entering an electerfied section and released on leaving it.
The weight (full) was increased to 503/4tons (16tons 16cwt. +
17tons 4cwt..+ 16tons 15cwt).
|Subsequent engines starting with No. 8750 were all built with improved cabs,
class PJ boilers and A.T.C., with the exception of the second No. 8700 which inherited
the cab and number plates of its predecessor. The class was now sub-divided into
5700, 8750 and 9700 condensers groups. To prevent steam from the whistles obscuring
cab windows small deflector plates were fitted to guide the steam flow over the
No. 9773 was the first engine to be modified and two
years later commencing at No. 3774 or thereabouts, a larger type was introduced.
This was standard for the engines with large cabs, the shorter pattern being
fitted to the earlier engines. Further improvements were incorporated in No 9795
(9/36) and subsequent engines with pocket steps welded
onto the bunker on the firemans (L.H.) side and additional handrails to facilitate
access to the bunker. Engines built prior to these modifications were gradually
brought into line as they passed through the shops. The weight was increased
to 49tons, 17tons - 17tons - 15tons.
In 1942 a new type of top feed appeared, with separate clackboxes housed in a much
taller cover than the Churchward pattern, and internal delivery pipes in place of trays.
The point of delivery was very carefully chosen to prevent trouble from local cooling.
No. 8770 and 5735 were the first of the older engines to be modified, and No.
4656 (5/43) the first to be built as new, although it did not seem
to have become standard for new construction
until 1944. From then top feed apparatus had been put on many of the older boilers
and some engines built with it, had lost it due to boiler interchange. Nos. 6750-79,
like Nos. 6700-49, had steam brake fittings only.
During the Second World War the " 5700 " class began to be used at Didcot Ordinance
Depot and spark arresting chimneys were fitted to Nos. 3709/21, 4601, 5710/44/52,
7709, 8738/57 and 9722 while No. 7709 also had the 'bird-cage' type. Nos. 5757
and 7713 had however acquired spark arresting chimneys by 1938 and 1937 respectively.
In -May, 1946, No. 7722 was fitted with winding gear for working the Pwllyrhebog
incline on the Taff Vale line, also one or two engines had the upper lamp iron moved
to the smokebox door.
Allocation and Work
So far as axle loadings would permit, the class was distributed throughout the system
and only a few sheds did not have them. In 1950 it was decided to allow the class
(except -Nos. 9700-10) to run over "Yellow" routes due to their negligible
hammer-blow so that by February 1954, only Truro, Abercynon, Treherbert, Aberystwyth
and Machynlleth had no allocation.
The distribution by Districts in February 1954, was London, 121; Bristol, 112;
Newton Abbot, 61; Wolverhampton, 125; Worcester, 33; Newport, 178; Neath, 139;
Cardiff Valleys, 83; Central Wales, 6. The other five were at Birkenhead, having been
classed as London Midland Region stock with effect from 19th April, 1953.
The 67XX were not as widely spread as the rest of the class. as they were purely
shunting engines with steam brake only. In 1954 they were shedded as follows;
Swindon, 4; Newport Pill, 20; East Dock, 1; Swansea Paxton Street, 2; Cardiff
East Dock, 21; Barry, 19.
Returning to the engines fitted with vacuum brake ejectors, not only were they
used for shunting and local freight working but were used quite extensively in
most areas for branch and short-distance main line passenger trains. With
comparatively light loads they often made some very lively running and were
occasionly used as standby engines for those of larger classes, and their efforts
to keep time with heavy loads were often accompanied by firework displays!
Under British Rail they were Power Class 4F and the standard livery was unlined
black, although there were exceptions that were lined, and many had the safety
valve covers polished. Nos 6760-79, 9673-82 were built with smokebox number plates
and all but Nos. 3656 and 3742 of the earlier engines were fitted later. It would
seem that all Swindon built locos had cast iron cabside numberplates but the
specification for contractor built numberplates was usually brass.
No. 7711 was transfered to the London Transport Executive in October, 1956,
and becoming L.T. No. L90 was repainted in lined maroon livery (the first of several).
By 1956, the closing of branch lines and the advent of diesel shunting engines
had combined to make the earliest engines of the class redundant and the first to
go started with 3/56; 5700/62, 10/56; 5792, 7711(L90).
The mileages of those withdrawn being between 500,000 and 556,000.
|5700-49||North British Locomotive Co. Nos. 23818-67||256||1929
|6700-24||W. G. Bagnall -Nos. 2381-2405||262||1930
|7700-24||Kerr Stuart Nos. 4435-59||263||1930
|7725-49||North British Locomotive Co. Nos. 23921-45||264||1929-30
||Yorkshire Engine Co. Nos. 2249-73
||Armstrong Whitworth Nos. 1131-55
||W. G. Bagnall Nos. 2422-46
||Beyer Peacock Nos. 6680-6704
||North British Locomotive Co. Nos. 24038-62
The Locomotives of the
Six-Coupled Tank Engines
Correct as far as known at March 2001.
|3650||Didcot Railway Centre
|3738||Didcot Railway Centre
|4612||Bodmin & Wenford Rly
|GWR no. 5764, LT no. L93||Severn Valley Railway
|GWR no. 5775, LT no. L89||Keighley & Worth Vly Rly
|GWR no. 5786, LT no. L92||South Devon Railway
|7714||Severn Valley Railway
|GWR no. 7715, LT no. L99||Bucks Railway Centre
|GWR no. 7752, LT no. L94||Birmingham Rly Museum
|GWR no. 7760, LT no. L90||Birmingham Rly Museum
|9600||Birmingham Rly Museum
|9629||Pontypl & Blaenavon Rly
|9642||Dean Forest Rly
|9681||Dean Forest Railway
|9682||North Norfolk Rly
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