GWR Bunker Styles
(small engines)
by Mikkel Kjartan
The many different bunker styles on GWR
tank engines can be rather confusing, so here is a brief description of
the major types. Note that these are in principle only the designs used
on the smaller four-coupled tanks, but the basic styles are widely applicable
to other tank classes also.
The drawings and data below are based closely on "Locomotives of
the Great Western Railway, Part 6" by the Railway
Correspondence & Travel Society (now out of print). Many thanks
to David Bell for helping with the page. Any errors are those of
the Webmaster only.
Early bunkers were made from iron, and had sloping fronts (1A).
Some were later altered to the square front version (1B). In due
course, fenders of various designs were added, as seen on the right.
In 1878, new steel bunkers were introduced
in Wolverhampton works(2A). Some had a prominent joint beneath
the flared tops (2B).  The
design was adopted by Swindon in the 1880's, and was developed further
with the addition of coal rails and/or fenders as shown here. From circa
1906, a standard design for this type had been arrived at (x1),
and this was used widely on the smaller tanks until grouping in 1923.
A few were given deeper fenders during WW1 (x2).
 The
517 Class and related 0-4-2T's were mostly built at Wolverhampton
works, and were turned out with their own bunker style during the 1884-1915
period (3A). In order to increase coal capacity, make-up pieces
were often added (3B & 3C). A few had actual replacement
bunkers fitted during WW1 (3D), while locos with enclosed cabs
had a square-front version (3E & 3F).
 The
rather austere "coal-box" (4) appeared first in 1886,
and was subsequently used especially on the larger eight and ten-wheeled
tanks. The similar type with sloping back (5) was used on the
experimental oil-burning "101" around the turn of the century,
but also on the Churchward 1361 dock shunters of 1909.
Around WW1 there was a need for increased coal capacity,
but the war left little time for implementing new designs. Some of the
larger eight and ten-wheeled tanks did recieve enlarged bunkers at this
time (6C & 6D), but apart from a few replacement bunkers
(6A), the smaller tank engines did not generally se any bunker
changes until grouping. In 1924, Wolverhampton works developed a deeper
version of their original pattern (2C), while Swindon took an
outset in the designs developed earlier for the larger tanks (6B,
6C & 6D). These soon became widespread on new tank classes also,
(such as the various versions of the 57xx class) and essentially lasted
in different sizes until grouping.
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