A couple of points and then I'll be quiet. The Delano boxcar snip looked to have a color cast. I took it into Lightroom and as small as the PNG is, it still revealed a blue cast over the entire image. I removed that and the colors look richer, less washed out. What's the point? That shot was probably under a blue sky that acted like a big blue light source, soft but blue. The same shot under a cloudy sky would have had a totally different tone. We can adjust white balance today, Delano could only do so with filters, either at camera or in the darkroom. Did he? Who knows.
Moreover, we don't know if the color cast was introduced somewhere in the steps that brought it to your monitor. I converted to digital photography in 2002 and it took several years for me to begin to grasp the mysteries involved in translating a slide or print from scanner to computer to printer, or God forbid, to four-color press output. (Just look at the variations in color repro work across the railfan press.) And even then the original slide or print might have had its own color bias. Finally, your monitor and my monitor may not 'see' the exact same 'color.'
Second, to Tony's point. I have models that have been finished in ways that would just not 'look right' on my layout, circa 1956. There wouldn't be that 'period theme' that Tony and Bruce seek. My several ACL ventilated boxcars, finished as from the shop in original and rebuilt schemes, just won't work on my layout, so they stay elsewhere. But a weathered FEC version works.
To me, the Delano images are so attractive because there is color harmony, many reds and browns, complemented by blue or green, and an overall warm tone produced by the Kodachrome of the era. It helped that the railroad scene was also full of warm tones, with few distracting colors. I try to find that kind of harmony in my modeling, even if the colors are not perfect.
Anyway, I applaud your quest and wish you success. You have caused me to think about all of these mysteries again.