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London North Western
Railway:
 Midland
Railway:
 Stratford
Midland Junction Railway
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LMS Route: Evesham to Birmingham
Harvington Station: mrhv1423
Passengers wait on the station's platform as a train from
Redditch is given the all clear to proceed to Evesham by the lower quadrant
signal seen on the left circa 1910. Tom Cook writes, 'the photographer was
David Hutchings and his subjects, the baby in the pram and the lady standing
alongside the pram, are my father, Stephen Cook, and my grandmother.'
As can be seen, there are two signals visible in the
photograph controlling the same bidirectional section of line through the
station. The signal on the left controlled down traffic travelling towards
Evesham whilst the signal seen above the bridge, with its arm pointed in the
opposite direction, controlled traffic travelling in the up direction towards
Redditch. To avoid accidents, each section of line (or block) was managed by a
token or staff. The token system was developed in Britain in the 19th century,
to facilitate safe working of single-line railways. For convenience in passing
it from hand to hand, the token was often in the form of a staff, typically 800
mm long and 40 mm diameter, and is referred to as a train staff. Such a staff
is usually literally a wooden staff with a brass plate stating the two signal
boxes between which it is valid.
Using only a single token does not provide convenient
operation when consecutive trains are to be worked in the same direction. The
simple token system was therefore extended: if one train was to be followed by
another in the same direction, the driver of the first train was required to be
shown the token, but not take possession of it (in theory he was supposed to
physically touch the token, but this was not strictly followed). He was given a
written authority to enter the single line section, referred to as the ticket.
He could then proceed, and a second train could follow. In the earliest days
the second train could proceed after a designated time interval, as on double
lines at the time. However, following the Armagh rail disaster of 1889, block
working became mandatory. Seeing the train staff provided assurance that there
could be no head-on collision. To ensure that the ticket is not issued
incorrectly, a book of numbered tickets is kept in a locked box, the key to
which is permanently fastened to the token, or is the token. In addition, the
lock prevents the token being removed until the ticket box is closed, and it
cannot be closed unless the book of tickets is in the box. Once a ticket is
issued, its number is recorded in a Train Register book, and the token is
locked in a secure place. This system is known as staff and ticket.
On the right of the photograph is a Gradient Post. Gradient
Posts are placed, facing the track, at each location where the gradient of the
trackbed changes. Gradients are expressed as a ratio, e.g. '1 in 200',
meaning that the track will either rise or drop by one foot in every 200 feet
travelled horizontally. The angles of the gradient post's arms indicate the
direction of the slope. The Gradient Post seen above has omitted the '1
in' terminology often seen on Gradient Posts, leaving just two sets of
numbers on each arm. Due to blurring on the photograph its not clear as to the
precise numbers being displayed on each arm. Nor with the post being out of
vertical is it possible to be sure as to the configuration (angle) of the arms
to each other. It is thought that the arm pointing to Evesham reads
'294' and the arm pointing to Redditch reads '344'. This would
indicate that the next section of line from Harvington towards Evesham was
rising at a rate of 1 foot in every 294 feet and conversely the section towards
Redditch was rising at 1 foot in every 344 feet. The length of the section of
line rising or falling depended on the topography of the area which meant that
the gradient of any railway trackbed would rarely be constant over any great
distance resulting in the level changing several times within the space of a
mile. In some places (such as the Lickey Hills) the gradient can be so steep as
to have a major effect on the way that certain trains were operated.
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