old marx o-27 switches and repair

What does soaking them in vinegar do? I've never heard of that one. Matt 

The vinegar soaks all the old crude, rust, dust, dirt off the metal.  Depends how long you want to soak it to see how much you want off.  On the tracks I soaked, some very very rusted, it took almost all of it off and then took light metal brush to get the rest off.  I soaked them in Dawn dish soap that got the residue off all metal parts.  Remember Dawn is what is used to get oil and grease off of birds where there is an oil spill etc.  Works great. 

I would not use vinegar on electrical gear.  The electrical coil or solenoids that move the switch are wound with insulated wire and vinegar is a weak acid, really acetic acid.

I have resurrected several Marx switches.  First I would scrape off all the rust and paint in the path of the movable section of track.  You must get the movable section to move freely.

If it still does not work freely you can the switch apart.  Use a Moto grinder and grind out the two rivits that hold the switch to the base.  Take base off.  Then pry the tabs up that hold the cover of the solenoids.  Clean the bar that is in the solenoid coils.  Be sure to remove any rust with an old knife or wire brush.   Oil up the pivot points.  Hook up 14 vac and to center post and alternate one wire to each end pole to check the working of the switch.  It must snap sharply to each position to lock into its position.  Install small nuts and bolts to hold the base to switch when done.

Charlie