MTH z-500, Adequate for 4x8 loop?

The Z500 puts out less than 3 amps at 18 volts. That should be enough for the passenger train, assuming the passenger cars are MTH and not postwar with more power-hungry bulbs.

Adding anything else may put you right at the ragged edge, to even over the edge.

Thanks. I hooked up the z500 to my 3x5 test track and put my Railking Illinois Terminal NS heritage SD70 and a new lighted caboose on it and it did well.  Hopefully when I put together the 4x8 the z500 will handle my passenger train on the outer loop.

The physical size of the layout is not the factor you need to consider when selecting a transformer.

You could use that transformer on a large layout if you provided enough power feeds to the distant track sections and the only thing that transformer was powering was a single train with few lights and a modest locomotive drawing less than 2 amps at peak.

Remember, the size of the transformer is affected by the power draw. Even a 4-by-8 layout can overload a transformer if the equipment is drawing too much energy.

I run a 5-car El train on a loop that has about 64 feet of track, and is powered by a single Z500. The El loop has 5% grades.

Thanks. I didn't think of this. I should be alright with what I will be running on that loop.