Transformers for Public Display

I don't know the answer, but it might help those more knowledgeable if you note how many trains, whether you will use lighted passenger cars, how many accessories and what type?  Probably also whether these will be Lionel conventional or similar locomotives because some MTH locomotives don't deal well with the basic Lionel CW80 transformer, which would be a typical choice for a simple layout. If MTH locomotives, I suspect most would recommend an MTH Z-1000 or something similar.  MTH is closing up shop and service on their products is still uncertain for the future. MRC makes some transformers for AC O gauge, but I'm not familiar with them.

Are the children going to control the speed? Or will the speed be preset and not available to the children?

The one I built used an MRC transformer and electronics from Dallee. Person would push a button, train would gradually start and run for about 5 minutes before coming to a gradual stop. Worked very well.

In terms of reliability, the Miniature Railroad & Village at the Carnegie Science Center uses ZWs + PowerHouses and they continuously operate for 8 hours a day 7 days a week without any issues.

Thanks guys. I'm going to run cheap can motor diesels like mid 90s alcos, fixed speed all day. Pulling a boxcar and lighted caboose.

That's a pretty light load.  25 watts should cover that ( say 12 volt track power times 2 amps max current draw under starting conditions  = 24 watts ) so a 50 watt or so transformer would allow it to run all day without heating up and have some overload room for kids stopping and starting the train every 10 seconds ( like kids will do )