Re: D&RGW passenger car brake systems

What is the pipe size of you second line? If it is smaller than the air brake line, than more than likely is is a air signal line. Look for tee's on each end of the car under the platforms. Another indication is if it parallels the air line, e.g. does the pipe end on the same side of the coupler, right side when facing, or does is end on the left side? If the car still has hoses attached look for a letter cast on the glad hand: the air brake hoses use type F gladhands, air signal lines use type H. The two are not compatible to prevent mixing the systems which would limit the braking on a train.
Steam line are generaly 1-1/2" or 2" pipe, and they end on the left side of the coupler.
Hope this helps
Paul