|
|
|
|
GWR Route: Banbury to Wolverhampton
GWR Route: North Warwickshire Line
Birmingham Snow Hill Station: gwrbsh1755
|
Great Western Railway 38xx (County) class 4-4-0 No 3804
County Dublin stands before the down scissors cross-over switches
at the end of platform No 5 with a South Wales express in 1925. The coach stock
is clerestory design. Built at Swindon Works in October 1906 No 3804 was part
of lot 165. The County class designed as express locomotives by George
Churchward, was influenced by American practice; with the outside cylinders and
valve chest cast in two identical pieces and bolted together to form a rigid
saddle under the smoke box. This arrangement eliminated the requirement for
multiple steam tight joints and became the standard for all future classes
having 18 inch x 30 inch cylinders and 10 inch pistons. The locomotives were
fitted with a Standard No 4 boiler operating at 200 lb pressure to produce a
tractive effort at 85% of 20,530 lb and this meant that these locomotives were
classified in power group C. No 3804 had a 14 element, 84 tube superheater
fitted in November 1909 to improve boiler efficiency. As built the maximum axle
weight was 19 tons, 8 cwt, which limited the locomotive to main lines and a few
branch lines (Route colour - Red). The locomotives were used for principle
expresses, but as more powerful 4-6-0 locomotives became available these 4-4-0
locomotives were relegated to cross country routes and in particular the
Birmingham to Bristol expresses where the Great Western Railway utilised
running rights over the Midland Railway between Standish Junction and Yate.
The Midland Railway limited this line to 4-4-0 locomotives
due to weight restrictions over the Stonehouse Viaduct. Only in 1927, was this
restriction finally lifted following work by the Bridge Stress Committee. It is
worth noting that the County Class locomotives had a reputation of rough riding
and this was found to be due to the hammer blow, caused by the amount of
counterbalance to the reciprocating parts of the motion and the short rigid
wheelbase. This dynamic hammer blow and not a locomotives static weight
was found to be more damaging to the permanent way. The calculations indicated
that the combined axle load (including hammer blow) of a typical County class
4-4-0 locomotive was almost 30% more than that of the prohibited Star class
4-6-0 locomotive, despite this later having both a heavier axle weight and
total weight. The Great Western Railway tried several experiments to improve
the ridding and in June 1924 No 3804 was given the eight wheel bogie tender
from the scrapped 4-6-2 locomotive Great Bear. This tender was
subsequently tried with other members of the class. No 3804 was originally
allocated to Banbury shed (BAN) in October 1906, but it was known to have been
allocated to Worcester shed (WOS) in January 1921 and was finally withdrawn
from Oxford shed (OXF) in March 1931.
Robert Ferris
back
|
|
|