Electrical pickup issues w/ On30 passenger cars

[AardvarkMine]

We've got a small set up of Bachmann snap track around the tree and a new On30 Climax and 2-4-4-2 to pull a string of the Christmas themed passenger cars around it.  Over the last couple of weeks two of the cars have developed major electrical pickup issues, giving the look of a Christmas themed disso train rather than a serene turn-of-the-century rail line.

While I'm not new to model railroading I'm a novice when it comes to tinkering and not very confident.  I've cleaned both the track and the wheels of said coaches but that hasn't improved the situation (and the 3rd coach in the set is working fine).  I was going to take the trucks off to check the wipers but I'm not confident I'm sure how to do that being that there is no obvious screw securing them.  I also note some wires going from the truck to the car body and don't want to do more damage than is already done.

Any suggestions on how to A) safely remove the trucks or B) troubleshoot the electrical feed issue would be greatly appreciated.  The fact these cars light up so nicely (normally) really makes the train and I was even thinking of getting some passengers and maybe re-doing the car floor mail isle ways (to hide the screws) to make them extra special for next year.

Thanks!
Art

[railtwister]

Removing the trucks on the passenger cars requires removing the roof in order to access the truck screws. If the track and wheels are clean, it is likely the pickups, but if I remember correctly, the passenger cars don't have wipers, but use the axles/journals to get the power to the truck frames where the wires are attached. If the journals get dirty, or have too much oil applied, the contact will be spotty, making the lights flash. Cleaning the axles/journals might help, just be sure that if you use any solvent or cleaning fluid, that it is kept away from the painted finish or plastic, because it may dissolve either. If the wheels squeak because they need lubrication, try a tiny bit of "Conducta-Lube" on each axle/journal (after you clean them first).

Bill in FtL

[AardvarkMine]

Thanks Bill, I'll give that a shot.  Is there anything special in getting the roof off, or will steady pressure do it?

You know... I even mentioned wanting to cover those screws in the OP... just never put 2 and 2 together.  *sigh*


(edit) 
Scratch that question, roof pops off nicely.

[AardvarkMine]

Worked like a charm!  Thank you!