If you follow what little blogging on here I try to do, then you will already know that I was given (happily) the daunting task of converting a large HO scale layout from ABS signaling to a very prototypical CTC system, which I was allowed to model after UP's CAD (Computer Aided Dispatch). While the way the system operates is very close to today's Union Pacific, the hardware on the layout had to at least give a feel for the Santa Fe, which is what the layout owner models. Good enough for me, just means I get to play with that many more types of signals.