Steve S.
With your comments you have advanced the dialog about RRFRS (Removing Rust From Rails Syndrome).
1) An oil pan tub is a great idea for cleaning 40-inch track sections! All my O-gauge track sections were 10-inch straights or O31 curves, and they fit nicely in a kitty litter plastic tub.
2) I placed two levels of track sections in the tub and "baptized" them all with Evap-O-Rust (i.e, immersion, not sprinkling).
3) Placing the track with the rail side down in 1/4-inch level of Evap-O-Rust (or whatever product) will do the job and may help spare the rail insulators and paint on the black crossties. The center rail insulators are made of fiber stock (not mere paper) and they hold up well to immersion in the fluid. I noticed that the paint on the UNDERSIDE of black crossties is more vulnerable to removal than the top side. About switches ... O22 switches have a paper insulating liner inside for electrical insulation (it's like brown Kraft paper). If it gets wet, it'll be ruined. However, it can be replaced; just remove the metal bottom plate of an O22 switch for use as a pattern, cut a fresh insulating paper, and install it. I use 36# paper stock for that purpose; it has a bit more heft than standard 20# paper stock. This may be the boyhood equivalent of cut-out paper dolls for girls!
4) Many train hobbyists affirm denatured alky as a "universal solvent," so it would probably do the job. However, Evap-O-Rust suggests using plain water. The product is biodegradable, non-toxic, and enviro-friendly. I hose down the track segments at the back yard lawn with a rinsing stream from the garden hose nozzle. I believe the water pressure may help loosen some black crud.
5) Evap-O-Rust will find its way inside the web of tinplate track through the underside seam. All to the good. Yes, it removes the "black crud" too -- the residue from overzealous lubrication, mixed with carbon, and "fried" from arcing on the rails. While drying the track sections, I strike them on the patio table top to shake loose any fluid trapped inside the web of the rails. Some guys remove all the track pins prior to derusting and then re-install and tighten them in the rails afterward with a spiffy pliers tool custom-designed for that task. I confess I'm not that fussy. Pipe cleaners inserted into the open rail ends is a good method! If I discover track pieces that are hopelessly lost to rust, I just toss them away and don't waste time (and expensive Evap-O-Rust fluid) on them. New tubular track sections aren't that expensive.
I didn't take pix of the process. I'll run another batch soon, and will take BEFORE and AFTER pix then. I should ask Evap-O-Rust for a royalty payment!
Your process is even more detailed than my first effort, so you are ahead of the learning curve and advancing the state of the art. Carry on valiantly.
Mike LCCA 12394
(ritrainguy)