I did some test runs with some rolling stock and engines on Super Streets and can run MTH Septa trolley (road number 2165) on the 12 inch curves, also can run the K-Line Plymouth switcher set. Don’t try diesel engines or steam loco’s as Super Streets is mainly for trolleys or handcars and rail speeders.
What won’t run on 12 inch curves even though it is short are the handcars or handcar sets, like the Coca Cola Bear set, may need 16 inch curves as they derail on the 12 inch curves.
I didn’t buy a set just the track and use a Lionel 1015 45 watt transformer for power as I just need to power one or two motors at a time. Also use Lionel’s Fastrac wire set to hook up power to the underside of a 10 inch straight, cut a notch for the wires with an exacto knife and a small pair of needle nose pliers.
So far the only drawback is that I have not found screws that fit the holes and can put the manhole covers back on, I have screws that fit but can not put the covers back on, going to a hardware store sometime this week to locate better screws.
To be honest with you I don’t know how well other stuff will do on Super Streets like a heavy steam loco or a big diesel(SD-90Mac) on the straight tracks, if something is too heavy it may slightly bend the track.
A tip for power wires is to use Lionel’s Fastrac hookup wires that have miniture clips on them as this hooks up to the underside of the 10 inch straight section, the 12 inch curve only has the outside rail hookup and no center rail hookup.
Recommend that you get the center rail pickup rollers replaced anyway.