Since we were discussing the D&RG cars lettered for "C.R.S.TRUST", I thought I'd show an Ed Bathke Stereo showing a train of these cars descending LaVeta Pass behind #22 "Alamosa", the first D&RG 2-8-0 (BLW 1877). The first four boxcars are 2704, 2400, 2355 and 2129. Of these, the first three carry only the C.R.S. Trust lettering and only the 2129 has D&RGRW lettering. Another 2-8-0 is in front of the caboose, probably to help provide additional braking. Note that two brakemen are atop the first car.
On the matter of different braking systems (Ames Vacuum vs Westinghouse straight air): when the Royal Gorge War between the D&RG and AT&SF was ended in favor of the Rio Grande, the Santa Fe found itself with a number of narrow gauge cars (freight and passenger) for which it had no use. Fifty of these boxcars, equipped with straight air brakes, were leased to the DSP&P in 1879-80. I have a photo made near Buena Vista that shows one of these AT&SF lettered boxcars (#9176) coupled to a DSP&P box behind two Nesmith stacked South Park locos. The AT&SF box is in the middle of the train with more DSP&P cars behind. So, there must have been a way to run the different brake systems together. There does appear to be an inordinate number of brakemen (5) on/near the cars. Go figure!