N Scale - Bunk of 16 pipes - 24 inch dia. X 20 feet long -- Use on switch machine or other places.

thingiverse

This is a bunk of 16 pipes that are 24 inches in dia. and 20 feet long. They that can be placed on a rack on top of the switch machine's slide or used as a train load or placed anywhere on the layout. This bunk has a flat area on the bottom and the middle back to help gluing them to a rack. Look at the other option if you don't need the flat area on the back. If placed on a deck with a rack you can push them back and forth to activate the DPST slide switch under it and also throws the turnout via the control wire to it. The DPST switch can also change the polarity of the frog. More on the switch machine and how it operates here .... http://1fatgmc.com/RailRoad/3D-Printer/3D-Printer-Index.html