Early pipe service idler flats

Mike is right on the brake wheels. According to Bob Richardson, John Norwood and Bob Sloan, the earliest pipe train cars were made up in 3 car sets consisting of two cut down flats on either side of a gon with its ends removed. The cut-down flat cars brake wheels were originally removed and tied to the deck on these three-car sets. The gon brakes were used for parking in this configuration.
Early pictures of pipe train service show some of these three car sets. Looks kind of odd with two flats together. The D&RGW apparently did not anticipate very well how much pipe traffic volume would eventually result, and only converted a few cars to start with. They were hoping the NG would soon die off and could be put out to pasture, so were not very forth coming with efficient, speedy service for the oil/gas company.
Until, of course, Bob Richardson inadvertantly gave the frustrated oil/gas company information about all the unused NG rolling stock scattered across SW Colorado that could be easily converted for pipe train service (chain saw magic).