winston-salem district

NW Mailing List nw-mailing-list at nwhs.org
Mon Aug 6 09:02:45 EDT 2007


Jeff-
Let's get back to the "automatic" feature that was, and
apparently still is, incorporated into the interlocking at
Walnut Cove. The components of the interlocking make
a decision based on one factor -- which train hits the
approach circuit first. There's no bias to railroad. There's
no consideration to priority. There's no consideration to
which train has the most tonnage. Direction doesn't
matter. The approach circuit is an arrangement of
signaltry that detects an approaching train. Apparently
the approach circuit for northbound trains coming to Walnut
Cove is in the vicinity of MP 113. When the train activates
the approach circuit, the components in the relay case
at Walnut Cove start scanning. Is there a train on the
bisecting route ? In this case the bisecting route had been
Southern's Winston-Salem Division. Is there a train in
the block ahead ? Once convinced that the route is
unobstructed, the home signal ( at MP 108.8) will clear. Only
then will the aspect of the distant signal change to be more
favorable.

When NS abandoned the track Greensboro to Rural Hall, the
bisecting route was eliminated, but apparently NS only modified
the interlocking. When a northbound shunts the approach
circuit, the interlocking continues to "search" for trains in the
block toward Belews Creek Jct., and maybe for those Winston-Salem
Division trains that'll never come.
Harry
Bundy



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