|The Walker's Train Describer consists of a clockwork
driven mechanical "Sending" instrument and an electro-mechanical
"Receiving" instrument. The purpose of the instruments is to send a
request from one point to another with a visual indication of what is required.
Each pair of these instruments has an identical dial upon which is fixed round
tablets showing various required movements (e.g. Light Engine to Down Yard) and
a pointer to indicate the tablet required.
In the photograph below, taken in Brighton Signalbox, are a "Receiving" and a "Sending" instrument, each of which is connected to the "opposite" instrument elsewhere.
The Walker's Instruments that were installed in Brighton Signalbox.
photograph by kind permission of Alan Elliott
|The instrument on the right is a sending one, note the
levers are outside the dial making the instrument resemble a ship's
steering wheel! The one on the left is a receiving instrument and the bell on
the right strikes once for each position the pointer passes.
When a request is sent for a particular move to be set up
the person requesting it has to carry out the following procedure:-
Upon receipt of a destination (other than "Cancel") the person receiving must acknowledge the receipt by sending the appropriate number of beats on the bell key regardless of whether or not he is in a position to make the described movement. Upon receipt of the "Cancel" indication, the person receiving will acknowledge by one beat on the bell key.
As with all things mechanical, it does sometimes happen that the two instruments can become out of phase. In this situation the instruments concerned should not be used until such time as an engineer has corrected them!
All photographs are copyright
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This page was created 3 July 2004