This awesome road chain system caught our team’s attention. We were looking for a project to complete a holiday train layout and ran across the road chain starter kit on cults3d.com. The designer has done a great job of creating a totally self-contained system which you can print for an HO scale road system. It only requires a limited number of components beyond filament to build. At the time of writing, the designer offers to packages on cults3d.com:
A ”Starter Kit” which gives you all the components to build a track and a Double Lane expansion pack. You can read all about them on the author’s links.
How this article fits into our category of “adapted designs” is simple. We wanted to use the author’s track but for N gauge scale with some additional changes as well. How this adaptation went, along with suggestions for anyone building this sort of system is what follows below.
Items Needed for the Awesome Road Chain:
- A roll of filament. We liked this Charcoal Gray color for our roadbed by 3D Fuel:
2. Some magnets. We found that these 4mm x 4mm x 1.3mm worked well to fit both the vehicles and road chain:
3. Vehicles. You have lots of choices here. For our system we started out using these diecast busses that are to scale for N gauge:
4. Some sort of suitable drive motor system. The author recommends using a continuous 360 servo. If you are building an HO system, we would recommend this also. For our needs in N scale, we went with a much smaller motor.
Printing the Drive Chain
Our team’s first challenge was to figure out how to print the drive chain. It is set up to be printed in place so that all you must do is pull it off the print bed and rotate the links to free them for use. The first attempts didn’t work so well. We decided this was probably due to the author using a more advanced Bamboo labs printer rather than a Prusa design. What our team discovered is that a common printer can print this chain perfectly with a few “tweaks” to the slicer we used. For those interested, here are the settings which worked for us using Simplify3d:
Using a nozzle size of .4mm, and PLA here are the settings that worked:
Extrusion multiplier .80
Extruder temperature: layer 1, 210C, layer 2 and up: 190C
Cooling 0% layer 1, layer 2 and up 100%
Bed temperature 60C
Layer height .3.
External thin wall type: Perimeters only
Internal Thin Wall type: Allow single extrusion fill
100% infill.
With the above settings we could print a chain segment each time that would be completely flexible.
Turning Things on Their Head
Our team is always looking at “turning things on their head”. And that’s exactly what we did with this system. The author had designed each track piece to be “bolted” to a fixed surface (such as a board) using metric M2 self-tapping screws (or similar). Since we were already going to have to modify the track system for N scale, we decided to change the track in a way that it could be used without a board as well.
The results worked out very well. Here is a video of how an oval shaped track worked:
If you want a nice “road texture” we suggest printing your track on a PEI sheet. That is what we used. It gives you great adhesion as well.
Redesigning the track in this way turned out to provide an extra bonus for our team. It makes the drive chain easily serviceable as the entire track does not have to be taken apart.
Instead of using a 360-degree servo, our team came up with a modified drive design that uses an N20 geared motor.
This motor provides more than enough power to drive the chain with a small layout and cars linked to the chain. We ran a “durability test” over several hours to see how the N20 would perform. The motor never became warm to the touch and handled the load.
Suggestions:
When using either the author’s original system or the modifications we came up with magnet selection and placement is key on both the vehicles and chain.
The 4mm x 4mm magnets fit perfectly in the chain. The vehicle’s distance from the roadbed affects the magnetic field. A magnet too close to the road will place a big strain on any motor used. Too far away and the magnetic field will not “catch” it. We found that on our bus units, the very front ahead of the axles worked best. However, this same position for a lightweight car caused it to nose plant and slowed the train tremendously. We suggest experimenting with a few different vehicle types at a time before purchasing too many at the same time that may not meet your needs.
Parting Thoughts:
If you would like to build your own road chain system, please visit cults3d.com and purchase the track design from the author. We would like to share our modifications with the author so that he can offer the updates described here to you as well. It would provide some additional opportunities for you to build different track designs.
If you enjoyed this article be sure to check out some of our other adapted designs.