Looking for CTC Drawings

Fellow Railroaders, I am working on a modern CTC panel using an industrial PLC and a touch screen. As my logic has been progressing (doing it in ladder) I keep hitting the wall on how to establish and manage more than one routing through the CTC system at a time…

Time for a different approach. Does anyone have any electrical drawings to an actual CTC panel? I would love to drool over them and see how the real guys managed the relay logic of competing routes and back checking of controls points.

My CTC is filling a block of double track on of my control points is pretty busy with 3 cross overs and 2 branches.

Any Help is appreciated.

John -

Welcome to the A&O Forums!

Regarding your specific question about prototype practice, the CTC machine itself was the equivalent of a computer display and keyboard connected to a serial port called the code line. All of the vital interlocking logic was distributed trackside in relay cabins, connected to the dispatcher’s office by the code line. Somewhere I have a schematic of a US&S relay CTC machine but that wouldn’t help.

Regarding your request for help, since you say you want a modern style CTC panel, I highly recommend that you look into Rod Black’s free CATS software that runs on Windows and Mac. It has a graphical editor for specifying your track plan and does all the interlocking logic for you.

You can see a CATS display on John Parker’s Fall River Division web site at:

John’s dispatcher uses a mouse but I’d imagine that a touchscreen computer display could also be used if supported by the OS.

BTW, at the time of this post Rod Black is the person on the right in the photo second row, far right.

Information about CATS can be found at:


JMRI can be found at:


Again, welcome! I hope this is helpful.