3 Track Signal Bridge Gantry.
50mm distance between track centres.
Poles are hollow with 0.862mm ID hole.
You can cut the finial off and replace it if you need to get to the top of pole.
Ladder is seperate. VR Signal Bridge #2 Ladder 33 Rung 1:87 Scale
https://www.shapeways.com/product/69TYHLM8W/vr-signal-bridge-2-ladder-33-rung-1-87-scale