Building the DCC-Controlled Train Order Signal System
of the key things we wanted to have on the Operations Road Show layout was
a system of train order signals located at each active train order station
along the modeled portion of the line. Owing to the modular nature of the
layout and our own preferences for making the best use of the features incorporated
into DCC, we established the following "Givens and Druthers":
- The signals must be designed to survive transport, without requiring that
we exercise an unreasonable amount of additional care in moving the modules.
- To that end, the signal masts must not extend above module surface during
- The mechanism controlling the signals must not extend below module frame
so that the module can be set on floor without damage to mechanism
- The signal system should not require any new electrical connections between
modules. After all, being able to simplify the wiring by including the signal
control on the train control wiring was part of the reason we chose to use
DCC on this layout.
- The signal system should not require use of a computer. We have avoided
any need to use a computer to operate any aspect of the layout-- we felt
that the control features built into the DCC infrastructure should be adequate
to do what we want.
- The train order signals should resemble prototype semaphore-style train
order signals, but for our immediate purposes need not be highly-detailed.
Additional detail can be added at some future date.
- In order to make it easier for new operators to determine the signal
aspect, each signal's indication must be duplicated on the fascia. This
is an idea we borrowed from Jack Ozanich's Atlantic Great Eastern.
- A two aspect signal (Red/Green) is acceptable for the way we wish to
issue train orders.
As we went along, we added one other feature to this:
- Since our train order stations consist of a train order signal, a clip
for hanging orders and a phone handset connected to our open-line phone
system, the signal control system should be able to incorporate the alerter
buzzers we use with the phones.
Bob Milhaupt designed our train order signal control system using off-the-shelf
control components from Digitrax and Circuitron to drive inexpensive homemade
train order semaphore signals at locations around the layout, coupled with
custom-designed mounting hardware to meet our module transportation needs.
He described his method of doing this in a clinic he presented on October 24, 2004
at the Capital Crossing convention of the North Central Region of the NMRA
in Lansing, Michigan. He has made an updated version of this presentation
available for download here.
For the clinic presentation, Bob went beyond the ORS layout requirements
and extended the design to support three-aspect (Red/Yellow/Green) signals.
The information on our signal system is presented as an Adobe Acrobat (PDF)
design and specific implementation plans, with mechanical drawings of the
signals and mounting hardware (4.5 Megabytes, Updated
document requires version 4.0 or later of the Adobe Acrobat reader, available
for free download from Adobe.
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John F. ("Fritz")
Milhaupt on behalf of the Operations Road Show, All Rights Reserved.