Single Track Stone Tunnel Portal for O Scale Model Trains

This is more detailed version of my original tunnel portal for O Scale Model trains like Lionel or MTH. The exterior dimensions are based off the MTH single track portal. The internal dimensions have been expanded to give more room for trains when the portals are installed near curves.

This is a modular design that can be printed on smaller 3d printers like the Davinci Mini.

The internal dimensions of the portal when assembled are:

single track width ~4.8 inches
146mm height ~5.75 inches

You can print the base pieces and rear connectors without supports. Both upper sections and the keystone need to be printed with supports. I recommend using a .2 resolution with a 15% infill. I have not fully printed this portal yet but the pieces I have came out nicely.

After printing I assemble the parts with gorilla glue.

I have provided the keystone_blank.stl file which is blank and you can customize for your own railroad.

The stone models used to texture the tunnel portal can be found here:
http://www.thingiverse.com/thing:959682