I am so grateful for the input and advice. I was hoping to use my SC-2 and not purchase all new modules. I will get a SER2, as these were purchased before 2013.
I'm still looking for help wiring a loop for two train operation. One train (#1) goes into a siding while the other (#2) loops around. Then the train (#1) in the siding moves out, onto the mainline, while the first train (#2) moves into the siding.
Does each independent loop need a TPC (a commuter train loop, a trolley end-to-end segment)? Or can a TPC be "shared"?