1970s lionel boxcar paint that is cracking/crazing

Woodsy

The easy way mitigate the paint deterioration is declare yourself a scale and realist model railroader.  In real life, newly painted or like new rolling stock is very rare.  Most of rolling stock I see needs painting or is full of graffiti.  As time goes by you will begin to over look or not notice the paint flaws as much.  Most of my trains have lots of flaws as they are 1950s and bought used and inexpensive.

Charlie

I'm guessing the cars weren't kept in a temperature / humidity controlled area. Cracking like that I believe is primarily due to thinner based paint and/or shellac type finishes (i.e., not acrylics) being exposed to extreme temperature shifts, especially extreme cold and/or dry conditions. I know many old (pre-1980s) guitars and basses have similar cracking in the finish, due to exposure to cold and dry conditions.

As Charlie says, weathering can hide imperfections in paint color and such, but for the cracked ones, I don't know if there's much that can be done other than stripping them and redecorating.

Yeah -

They never lived in an attic but were box-stored in basements... Or worse... a basement closet for a number of years. Next to the sump pump 😳🥴🙄 But they were in forced air HVAC homes (greater air circulation than in radiator heated homes) but still far from ideal - and more humidity than the living spaces above.

One box seemed to have something like chemical induced discoloration, I didn't get pictures of those before I sanded & repainted. This is the first box with cracking. Anyways...

I have never seen damage like that from properly stored trains.  If not one else chimes in with similar damage, I would guess that this is a storage issue [heat, humidity, wrapping paper etc] rather than a manufacturing one.

my solution for the cracked paint.

I have read here and in other forums about methods for  removing paint from plastic shells. I was skeptical but ended up with a boxcar that looked like this (see pics) Anyhow - I wanted to try the brake fluid method because after a week-long soaking in TSP enhanced tide powder it only removed some of the black screen-print lettering and I figured what do I have to lose at this point?... So, inot a brake fluid bath - after soaking for 3~4 hours the paint rubbed and peeled off clean with a scotchbrite pad and stiff bristle toothbrush. The brake fluid is messy and no good for you - so wear some gloves and wash the shell and tools with lots of warm soapy water. I rinsed the shell clean and dried it for the afternoon. Sprayed with a Tru-Color rattlecan in boxcar red and left to dry/cure for 24 hours and then I applied some k4decals water slide decals. Tomorrow it will get a dull/matte coat of Krylon Matte Finish to knock down the decals "source-y" look.

If you look closely you will notice the repainted bottom right ladder rung still has a small miss from the spray can. AND my barefoot checking the shell cleaning in the garage before hitting the sack

Had success in whitening a yellowed postwar boxcar by soaking it for weeks in hydrogen peroxide.  The car was unpainted so can't say what would happen to a painted car.

that is the same kind of stain/yellowing some of my cars had. i wondered about whitening my miller 9802 boxcars with hydrogen peroxide after finding a couple posts about it. I should have tried it - or at least tried it on one of the cars I chose to repaint.

Placing it in the sun accelerates the process.