I run a 140 foot mainline folded dogbone, and it's powered by a single PH180 transformer. I've had three trains (all with smoke) running at the same time on that mainline without any issues, the total measured amp draw was right at 6 amps, still some headroom for the 10A PH180 transformer.
If you do anything with power, I'd probably consider moving the accessories & switches to a separate power source. If you haven't already done it, I'd also have independent switching for each siding so you can turn power off on each of them.