Trackwork Handbook

 Appendix 8: Detection and Signaling

Appendix 7: DCC Reversing     Contents

Comprehensive documentation of  the V2.2.0 MSS Standard is now available. Information is included for both developers and users.

Methods for installation or retrofitting of two types of IR detectors are described in the following articles:

This Heathcote IRDOT note shows you how to adjust the IR detector time delay time.

The OBUB-3, designed by Gregg Fuhriman, makes MSS installation much easier and more compact.

If you wonder how signals should operate, there are several resources that you might find helpful, expecially if you're an ATSF modeler. One is a detailed summary of the most likely operation of signals on the single track Second District (the "Pasadena District") in Southern California. This page was created for me by Carsten Lundsten with help from Barry Draper. Carsten has extensive information on signal operation for North American railroads that you many find helpful. Barry Draper has created three documents describing prototypical practices that are intended to be helpful to modelers. Barry's documents include: Signal Placement for Model Railroads, Santa Fe and Southern Pacific Signal Practices, and Southern Pacific & Santa Fe Signals.

If you wonder how turnout position is determined on the prototype, here is a photo of Santa Fe's "circuit controller and switch indicator at hand thrown switch". A drawing for this device can be found in The Chief Way Reference Series, System Standards, Volume Two.

I prepared a summary of Carsten's information for implementation on the Shandin loop module.  Both Carsten and Barry Draper were helpful in making sure that I got it right. There were some of the conditions that I couldn't implement in the absence of the ability to sense the direction of trains.

   Appendix 7: DCC Reversing     Contents 

Gary M. Green