Tunnel Portal, Single Track (OO)
A single-track tunnel portal at OO (1:76.2): 70.9mm wide and 86.6mm to the top of the parapet, with a 55.1mm bore springing at 39.4mm — off a 4200mm prototype bore with a 600mm arch ring. The ring comes out 7.9mm, so it is a genuine arch rather than a hint of one. Print it on its back: the bore becomes a vertical hole through a 5.9mm plate, the crown never has to be bridged, and the one feature that would otherwise force supports costs nothing. Voussoirs and brick courses are deliberately not modelled — at OO they would be a fraction of a nozzle width, and a smooth face you can paint beats a mushy one you cannot.
from £5.72example, in PLA
Example pricing
A guide only — not a fixed quote. Final price depends on material, quantity, print orientation and printability.
| Material | 1 unit | 5 units | 10 units | 25 units |
|---|---|---|---|---|
| PLA | £5.72 | £24.04£4.81/unit | £43.50£4.35/unit | £97.31£3.89/unit |
| PETG | £6.05 | £25.40£5.08/unit | £45.96£4.60/unit | £102.81£4.11/unit |
| ABS / ASA | £6.78 | £28.46£5.69/unit | £51.49£5.15/unit | £115.18£4.61/unit |
Per-unit prices fall with quantity. Larger batches are cheaper still — ask for a bulk quote.