Model Railway Tunnel Portal Double Track Modular Design 3D print model

Recently, I have been working on a tunnel for my model railway club, and as I was working on it, I decided to do a very similar design to share and could easily be used for a railway bridge.

This design has been designed to be printed inverted and, therefore, will not need any supports. I have printed several of these now without supports, and they have come out well. The tunnel is a stone brick design and has several parts that are enhanced to improve the look.

Whilst researching this design that tunnels come in so many different forms, and the surrounding support walls also come in lots of different arrangements. Therefore, as I develop this design, I will be adding several add-on components to help with building tunnels and bridges. (I am starting this project in April 2025 and will add components going into the summer of 2025.) I am also adding a single-track portal and add-ons.

The add-on components I’m looking at adding are:

Tunnel Side Extension Support Walls (also the ability to have two tunnels next to each other) Tapered Support Walls Straight Internal Arch 2nd Radius Curved Internal Arch 3rd Radius Curved Internal Arch 4th Radius Curved Internal Arch

Curved internal Arches will be made up of 2 degree and 6 degree segments, can also be formed with other arch sections to form exactly what you need that is not 2nd, 3rd or 4th radius.

designed at OO gauge, 1/76.2 scale but can easily be scaled for other gauges.for HO gauge print at 87%, 1/87 Scale,for TT print at 63.5% 1/120 Scale,for O gauge UK at 175%, 1/43.5 Scale,for O gauge International print at 158%, 1/48 Scale,for N gauge print at 51.49%, 1/148 Scale

The examples in the pictures were printed on a Bambu Labs A1 FDM Printer.As normal with my designs, there is a balance between accuracy and printability, hopefully not affecting the look of the model too much.

For FDM printing, I used a 0.4mm nozzle and a layer height of 0.12mm using PLA or PLA+ filament.

If you like my designs then please would you support me through my Patreon account - https://www.patreon.com/PJD1974, any money raised helps me research, design, and develop new items for me to share. For £1 a month, you will give me basic support and for £4 you will get insight into my new designs and be able to contribute to my future projects.

Please also check out my Website https://sites.google.com/view/pete3dprintinghelp/home