The file 'Double Track High Speed Tunnel Portal . N-scale 3D Printer Model' is (stl) file type, size is 24.7KB.
A modified version of a high-speed model train tunnel portal, with straight tunnel liner.
Sorry, can't remember where I got the original.
hi-speed_tunnel_entrance.stl | 53.4KB | |
hi-speed_tunnel_entrance_1.stl | 24.5KB |