Postwar 345 Culvert Unloader Voltage too High

Check the string - I bought one used at a local hobby store a few years ago and found the string had become “waxy” - there was very little friction between the string and the pulley resulting in very little pulley movement with each string oscillation.  I believe it was all original.

I cleaned the string with some alcohol which helped for a time and also scuffed the groove in the pulley with some fine grit sand paper.

I eventually replaced the string and replaced the spring at the same time.  Works better now - still not winning any sprints - but it is consistent and looks realistic to me.

- Luther

I agree with Luther’s suggestions.
In addition you might want to try different thicknesses for the string if not satisfied with your new one.
I used a Lionel PN string but test 3 different braided fishing lines to get the best results.
also the air gap between the solenoid and string attachment could be adjusted by bending bracket.
I bought both the loader and unloader early this year and it took me a month to get them working good.  
also check the gantry mechanism.  To get it working good you must minimize the force that is required to move the loader.  Clean it thoroughly to remove any grease or oil or grime.  Squeaky clean.  
good luck.
requires lots of patience and testing different combinations of string and spring force.
Bob

Luther and Bob, thank you very much for the encouragement.  I will look forward to having it run better than it ever has.