I still have one more Box Car Red rattle can to try. Unfortunately the Scalecoat II Oxide Red Primer can I have on special order has not yet arrived at my local hobby shop. It probably has to come ground freight from the east coast to California so it may take a while.
In the meantime I have what I think may be the winner already. The color I am aiming for is the SP Freight Car Red used by both PFE and SP. There are two measures of "closeness" to this color I am using. The first sample is a comparison with on page 419 of Tony Thompson's massive PFE book (2nd Ed.) where there is a drift sample reproduced as accurately as possible for printing. The other is PBL' s Star Brand SP/UP Freight Car Red which I have airbrushed in the past on a model I use for comparison. There is a long discussion of SP paint colors at http://modelingthesp.com/Prototype_Equipment/S.P._Paint.html.
And the winner is Tamiya Fine Surface Primer Oxide Red, Item # 87160-800. Again it is not quite an exact match but given all the variables it is close enough for my personal Rule 1. (This was not a scientific method study.)
PFE Book Drift and Tamiya Oxide Red Primer
PBL Star Brand SP/UP Freight Car Red and Tamiya Oxide Red Primer (the B-50-25 from an Andy Carlson/IM kit was air brushed with the SB paint when I could still use an airbrush)
And the Tamiya Surface Primer can go on in one coat. It is fine enough that I think a second would still not obscure details
Again your rattle can painting results may not be the same as mine. But I think I may have solved my rattle can source to replace an air brush problem. For the one or two cars a month I might paint FCR it will do even on expensive resin kits. And I only have to clean the spray cap in a very small bottle of Tamiya thinner after spraying.
I plan to show the full comparison of colors I tried when the Scalecoat II primer arrives. I still haven't tried the Preval sprayer. I may try it with some Vallejo Air acrylic "rust" sold as BCR by Micro Mark that I bought a couple of years ago.
I plan to try the Tamiya primer on a less expensive kit than the Westerfield B-50-15 I am building.
I will also have to search for a rattle can solution for "daylight" orange used on PFE car sides and the SP dark olive for arch roof and heavyweight passenger equipment.