Got supplies to build a custom DC controller today. The plan is for it to be able to power 3 isolated sections of track at once (the yard and both of the mainline loops will have a controller each). The individual controllers are rated for 48V, 20A and I’ll be running them at 12V, 3A max so they should be just fine.

This will be significantly cheaper than buying 3 pre-built DC controllers, if it works.