Street Running HO Model Railroad Track

This is a “proof of concept” level experiment. I was visiting the California State Railroad Museum, which is in an the old Southern Pacific roundhouse, and saw the rails embedded in the floor. There is also a great model railroad exhibit on the 3rd floor, and I noticed how difficult it is to make realistic track that is “street running”, or just what is common in industrial facilities (like the Reading & Northern track into a warehouse for the cover photo), light rail passenger stations, and engine shops (like the first floor of the museum). In particular where the rails seem to disappear into the floor/pavement. The accuracy required to have the rail just slightly above the pavement, right up against the outside of the rails, and the slot for the wheel flanges is difficult to do by hand. Then I saw what the British are doing with Templot, making custom track, and I thought I would give this a try.

So this model is a simple section of track to test of 3d printed trackbed (the rail has to be purchased) can work and look realistic. I think that this is a viable concept. The cars and locomotives I tried ran normally. I have tried this section of track with several different types of rolling stock, but not by any means all the possibilities. The first model is an S curve, with a straight section, nominally 18" (450 mm) radius maximum, 15 degree turns (in the FreeCAD file and step file). The 3mf file is cut down to fit on my Trident. I am thinking of making a set of different segments that could be joined together, so this is a work in progress.

The profile is for Micro Engineering Code 70 rail, and I was able to feed the rail in from one end through the curve after rounding the leading edge of the rail with a Dremel. 

To get the cobblestone look I set PrusaSlicer Print Settings to:

• Layers and perimeters/Single perimeter on top surfaces - Topmost surface only
• Infill Top fill pattern - Hilbert Curve

I selected Variable layer height - Adaptive (default settings) because of the small detail for the rail base.

I have included the FreeCAD 1.1 dev file if anyone wants to play with this. If you know CAD then making different floor/paving profiles and track centerlines should be easy. And of course FreeCAD is free.

Update - the acid test for this concept is an interurban curve in a street. Per the NMRA ‘Overview of Interurban’ the standard street curve has a 35 foot radius, so I made that. I was able to feed in the rail with gloves and sharpening the front of the rail. The gloves are important; I cut my fingers putting in the rail on the first prototype. I also had to help a little with a pair of pliers.

I have posted step files of the original straight plus S curve, a grade crossing, and the 90 degree 35 foot radius turn. Of course this is just a concept level development. To put into a layout, the street itself, or the engine house floor, etc, would be incorporated into the model before it is printed. I also posted the updated FreeCAD 1.1 dev model.