I am still working on this stalling issue and my problem is with Atlas-O switches. ( other manufacture’s switches may have similar issues.)
For some reason Atlas chose not to electrically connect the inner outside rails that connect to the frog electrically. In several configurations (as dead end spurs and other complex track arrangements) this means that the frog is not grounded. Running electrical ground to these inside rails powers the frog and allows the non powered wheels to pickup ground much better. So I am in the process of installing grounding wires in all the switches on my UNION FREIGHT switching layout.
With the grounded frog and full width pickup rollers I may have solved my stalling problem.
(I also found that I need to power AND ground the converging rails on my double slip switches.)
