Need advice for repainting rolling stock

Rob, I've tried all the methods that have worked for others, here on the Forum, but nothing worked until I soaked cars in 91% alcohol for days or weeks.  Only K-Line cars would shed all their paint but Lionel, MTH and Atlas cars are even resistant to the 91% but at least the lettering came - off leaving a shadow.  That's some tough stuff!

My only suggestion is that you soda blast and get the cars ready for paint and then soak 'em in 91% for a while, scrubbing with a toothbrush every few days.  GOOD LUCK!

I've used Purple Power degreaser, Easy-Off oven cleaner, Dot 3 brake fluid and Testor's Easy Lift-Off ("ELO") all with varying degrees of success for me. Each required soaking for at least a day or two. In my experience, the oven cleaner and brake fluid worked the best for me. For really tough stuff, I'ved also used 600 grit wet sanding on flat surfaces, being careful not to hit any details. Finally, I've also used a grey primer before my color coat to help prevent any bleed through or shadowing.

I've never done this, but I thought what @Richie C. said about the primer makes sense.  I would have thought there had to be something similar for this application to Kilz for water stains on drywall.

I coat of grey will certainly hide color differences.   I have been doing this for a little while now.    However, if the lettering has changed the surface - ie made it smoother or indented or something, it won't do anything there.

The grey is not a primer per se, just a color grey, generally from the same brand as the finish coat.  

I have used K4 decals on a few recent projects and did find them overly thick.   I found them easy to work with.    I did notice the white lettering on O scale cars is not as bright as other brands.

Rob; I’ve had good results removing existing lettering by lightly sanding those areas. After washing the car and allowing it to thoroughly dry, I apply a coat of Rustoleum 2X Ultra Cover Flat Red primer. Once this has dried, apply your final color then decal.

Not only does this eliminate any “shadow” of previous lettering, it also provides a superior surface for applying the new decals.

Curt

The use of fine sandpaper has crossed my mind, but I have not tried it yet.  I wanted to consult with some of the best on this forum and hear someone say, "try sanding" before I went to that step.

This project was so much fun I see myself doing several more, plus I know I can do a better job with more practice.

Re: K4 Decals.  @prrjim made the same comments I would have made.  Because the decal film is so thick, they are extremely easy to use...they simply do not hide well and attain that "painted on" look unless some surgical trimming is employed.   K4 does not yet make GARX decals for Frisco, so I "decal-bashed" the Frisco cars with a combo of QA&P GARX decals and Frisco 86' auto parts boxcar decals. (all from K4).   The only portion of the Frisco decal set missing was the slogan, "southeast-southwest".

The road numbers for the cars I repainted may not be accurate.  QA&P leased cars were numbered in the 505** series and Frisco in the 500** series.  I do know that QA&P leased 35 of these cars, but I never found a roster of exact numbers.  The numbers used were simply the ones provided as printed along with combos of the extra numbers usually provided on a decal set.

The work I do would probably make @SIRT chuckle, but if I could get his attention for only a minute, I would like to hear anything he has to offer.  I own one of his cars, and his work is astounding to me.

Kind of too late now since you repainted them, but I ALWAYS strip my models to bare plastic to avoid this problem.  91% Iso is my go to.  Some manufactures paint comes off easier than others.

STRIP

PRIMER

PAINT

We have had this discussion on our latest zoom meeting, some experimentation has shown on Lionel/Flyer, painting without stripping has been better.

I found the recent production of Flyer paint near impossible to remove.

Ray