With the recent greenish B&O Rapido USRA boxcars, the STMFC list threads have concentrated on effective workarounds on decorated shells.  


Here are the basics:


Prototype:

B&O freight car brown was the B&O house car color until 1945.  It consisted of an iron oxide pigment mix to achieve the brown color, mixed with linseed oil daily as needed at car shops systemwide.    Prototype color is best expressed by a detail from a 1943 Jack Delano slide at MILW Galewood yard freight house of a later M-15 subclass recently shopped with plain wood ends and freshly painted.





Model:

A decent out-of-the-bottle brown paint match is Tamiya XF-64 red brown military model camouflage paint.   It can commonly be found in hobby shops, on-line and brick, that sell military models.  ExactRail and Fox Valley matched this paint to good effect for their brown M-53 wagontop versions, as well as a B&OHS brown Red Caboose M-26 custom run years ago.

Rapido strove for this color on the B&O M-24 USRA SS boxcars but were keenly disappointed by their Chinese counterparts.

paint link:  https://www.tamiyausa.com/shop/acrylic-paint-flat-23ml/acrylic-xf-64-red-brown/

Web page says out of stock, yet this is the manufacturer site.  Plenty of paint at retailers.

On Tue, Nov 15, 2022 at 09:27 AM, Jim Mischke wrote:

B&O freight car brown was the B&O house car color until 1945.  It consisted of an iron oxide pigment mix to achieve the brown color, mixed with linseed oil daily as needed at car shops systemwide.    Prototype color is best expressed by a detail from a 1943 Jack Delano slide at MILW Galewood yard freight house ...

On the other hand, here's a link to another 1943 Delano photo, this one in IC's lakefront freight yards. This one won't help much with the exact shade for B&O brown, but it may suggest another approach to dealing with the erroneous color reported on the Rapido batch. :^)

I've read that the B&O paint weathered badly, as did some other iron oxide based paints of that era. It's well known that rust changes color as composition and hydration of the various iron oxide and hydroxides changes. More or less "pure" iron oxides form the basis of a wide range of pigments between yellow and black. I can readily imagine that reactions with the atmosphere, especially the sort found in a steam era railroad yard could affect the composition of iron oxides in pain pigment once any protective coating is weathered away, and shift the pigment color, in addition to accumulation of grime and other weathering effects.
FWIW, don't forget that Jack Delano's OWI color photography was with early Kodachrome which was not the same as the film many of us remember and love. Whether it's due to the original film's properties or processing, deterioration over time, or artifacts of scanning or display on our monitors, the color balance is often noticably off. 

Jack Mullen

On Tue, Nov 15, 2022 at 11:45 PM, Jack Mullen wrote:

On the other hand, here's a link to another 1943 Delano photo

Well, there was supposed to be a link.
Here it is; B&O boxcar center foreground:
https://www.loc.gov/resource/fsac.1a34787/

Jack

On Wed, Nov 16, 2022 at 01:45 AM, Jack Mullen wrote:

I've read that the B&O paint weathered badly, as did some other iron oxide based paints of that era. It's well known that rust changes color as composition and hydration of the various iron oxide and hydroxides changes. More or less "pure" iron oxides form the basis of a wide range of pigments between yellow and black.

And green. Al Westerfield told a cute story a number of years ago... With a degree in chemistry, one of Al's first jobs out of college was at Helene Curtis, in charge of the process that made the oxide pigment used in rouge. He said the trick was getting the reaction to yield the desired deep red color without taking on a greenish tinge, which of course ruined the batch. Since Al is a chemist, he cited all the formulas for the various colors of iron oxides, and since I am not, I have long forgotten them.

Dennis Storzek

Zooming in on that car it has everything from raw metal, rust and of course the faded paint on the sides.  There is a black and white photo of a M53 wagon top in the RPC that covers the wagon tops that has similar failed paint.  The photo of that car was 1952 I believe not 100%.  Could use the above photo as inspiration on the M-53.

Scott McDonald