K-Line MP15 diesel Rust Issues

Use a dremel with a wire wheel.  Then apply a coating of CRC 2.26

Not sure about the board.

Was it new or used? Maybe it was underwater at one time? I have 6 K-line diesels and have not seen any rust on them. If the board is corroding then I would say it went for a swim or stored in a very humid environment. Give it a good cleaning and see how it goes.

Bob

This was a used locomotive. I agree, I was thinking it was the victim of a humid environment. 

To start with, rust does not "spread" from one item to another; it's not a pathogen.

Looks like the loco was submerged in water for a short while, causing some eventual damage, but not enough to totally kill it. Mere "humid environments" (I live in one) are blamed for a host of ills that they do not cause. 

As recommended, clean it (carefully); use a toothbrush or the like on the boards to clean them and remove tiny metal "hairs" that can grow on old circuit boards.

The electronics (it's just a reversing unit) can be replaced easily for $40 - $50. Electric RR Co. or Dallee Electronics. 

D500 posted:

The electronics (it's just a reversing unit) can be replaced easily for $40 - $50...

Or $16.50 at The Train Tender.

Evaporust.  It is easy on most paints. It took two days solid soaking in it to even begin to degrade prewar Marx litho. I would be fairly confident the motors winding lacquer would laugh at it. It can be found most anywhere anymore X-mart to big box DYI.

The water rinse etc. is no big deal if the metal is dried fast and fully. 

For boards I'd just brush it clean, maybe wipe some Evaporust to work on rust stains. Same thing on the water. I used to throw cabinet video game motherboards into dishwashers (no soap...chlorine is bad). Relays and fans are a slight concern; open relay cases after, forced air at fans for 24hrs is usually enough. I always wait 48 hrs before introducing power again.

Penetrating and regular oils with brass brush agitation is the old school way, but I am not so sure how the plastic would like some of those, so that way I'd be breaking it down to parts for sure.

Oil will slow or even prevent rust creep.

PS - the CRC 2-26 is plastic safe and perfect to use on rollers due to its conductive properties.

Thanks guys!