REPORT OF MR. ROBERT B. LINES.
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show white or red as the line is clear or blocked on their respective sides. B shows the internal mechanism and connec-
Plate XV.
I_
tions, with the addition of duplicate sets of bells and plungers (P 1 and P 2 ), not shown in A, which are used for signalling the forward movement of trains. There are other forms of the apparatus, but this is the most complete, and was the one chosen for exhibition at Vienna.
The figure shows the up-track " blocked ” and the down- track clear. A "down” train, we will suppose, is about passing the station. The signal-man has four things to do :
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