135/180-watt power house sole power input?

There should be a lot of layout with only PH180's or PH135's  I use the two silver boxes TPC 400's as off/on switches, but the TPC's can be used for conventional variable voltage control.  Parallel PH 135 (lower left) supplying power to the TPC 400's center bottom.  Keep in mind that off/on is via the small switch on the Power House Transformer.  The TPC 400's are controlled by in my case a Cab1 Handheld remote.

No need for a variable transformer... But having a separate 12-14v supply for switches or other accessories is useful.  The 18v from the PH may be too high for your switches.

i use the brick from a MTH starter set as a 14v supply.

No, there is no need for anything else.  I run my TMCC layout with 2 180 watt PowerHouses and some accessory transformers with fixed taps (no handles).

I use the accessory transformer (a K-Line PowerChief 120F) to power the switch machines.  I don't use track power for switches.

George

Thanks,

Mario

I use the 180 watt PoHos for railpower only but they are linked to TPCs which enable me to program for conventional variable voltage operation from the Cab 1.

I operate track switches with Tortoise Motors powered by a 12 VDC wall wart [a HO Power Pak as backup].

On a larger layout, now dismantled, as does Mike CT above I  followed the practice of paralleling 135 watt PoHos.