HOn30 better running locomotives
The best trick, besides cleaning, proper lubrication, and a lot of extra weight, is to add additional pick-up wires.
On a Bachman 0-4-0, a set of wires between the wheels almost looks like
a sanding line, and improves running by a tremendous amount, with reduced
lower running speed and virtually no stalling.
On a Kato N-gauge SPUD, a set of wires is soldered to small brass shoes; these are unnoticable in normal running.