Today I replaced the three older 1994-1995 era Lionel powermasters with three Lionel 6-37146 Legacy powermasters, each programmed as track one for my three intersecting loops and I am totally satisfied .
I can now run all my MTH original protosound (proto 1) to their full potential including flawless sound with my Cab-1L remote. Horn, bell, coupler firing, FYS announcements, great speed control.
I had previously tried the non-polarized capacitors to no avail. I had also previously installed my homemade BCR's in all my proto one locomotives.
I recently decided to rewire my layout with some double throw double pole center off toggle switches so that I could choose to run my selections of locomotives of original protosound along with my Lionel and MTH command engines. Actually the proto 1 now run so good with all the features I think it would be a waste of money to convert these to command.
This forum has always given me lots uf useful info, thanks to all who responded.
Tom