Turnout Control
Goal
When the dispatcher/computer system is off, turnout control
remains with the local panel.
If the dispatcher is on, turnout control is from the
dispatcher's levers, and the local control is ignored.
The dispatcher can return control to the local panel
by flipping the "Switch Lock" toggle to the unlock position.
Signal Levels
All signals are active low.
For turnout position (Normal/Reverse), Reverse is
considered active.
For turnout lock (Lock/Unlock), Lock is considered active.
This will allow local control of turnouts if the
dispatcher control electronics are turned off.
Alternatives
The local turnout control in Chubb's book
has three-position toggles on the local panel
(Remote,Normal,Reverse).
This was not chosen in order
to minimize the complexity of the
local panels.
Separate lock toggles on the local panel were also ruled
out to reduce local complexity.
Commercial Possibilities
CVP AD4MD
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EMRA Electrical Design
Most recent update: 2011 September 14 by
Mark Johnson