LT1Poncho
Thanks for the comments. The Marx 1590 have been problem free for Marx locos forever. Initially I modified a 12 vac transformer to be 14 vac by removing some primary coil wire and the switches snap into position even the five sets that operate as pairs or two at one time.
Lionel locos and cars with pickups had issues which had to be addressed. The first was some Lionel Pickup rollers got hung up in gaps. There is a reason Marx used sliding pickups besides the lower cost. The long known cure was installing track pins or nails in the center rails, which close the gaps, as shown below.
More recently, with some more modern Lionel cars with roller pickups, the pickups roller got caught on the end of the Marx switch inside rail points. See picture below for my first cure, which was crushing down the top end of the center rail. This helped on most Lionel cars pickups.
On a few of the Lionel cars the crushing of the center rails, like the above fix, did not work. I then added a small piece of nail with a round by file tip worked better and now my cure of choice as seen below.
The best thing to improve the layout operation was to apply NO OX ID special A conducting grease as a track treatment. Slow train operation, with conventional operation that has about a 6 volt minimum, has improved greatly and track cleaning has not been required since over a year.
Charlie