San Juan Coach Help....

To all,
I have a question about the heating pipes on the San Juan Coaches. When looking at photos of these coaches you can see the heating pipe between the needle beams. They come out the edge of the car travel down the side to the other needle beam and then back out of sight. The are not horizontal, they look to have a slight slope in contrast to the bottom of the coach itself.
Can anyone help me figure out where they went from there? Or have a steam pipe diagram of how these looked under the car?
Last time I was at Knott's, I don't remember seeing any remains of the steam pipes but I wasn't looking specifically for them and it's been at least 4 years.
Thanks in advance,
Kevin Cook