Let’s Make Tracks! Is part 5 of our “Lets Build a Train” series. With your GP38 complete you need something to run it on, right? Well, how about some nice 3D printed track? Depronized (Designer of the GP38) did an excellent job, once again, of creating his own track. What we wanted to do in this article, is show you how to not only print his track, but to make it “two-tone” (as was done with the GP38 body), giving your rails a nice silver and black polished look. This can be done using any common single extruder 3D printer. So if you are ready to get hauling, well, let’s make tracks!

Here is a list of things you will need to make your Tracks:

1. Depronized’s track download. You can download it on Thingiverse.com .
2. PLA filament for the “base” of the track. We used Solutech Real Black for the track ties.

3.  PLA filament for the “rails” of the track. We used Solutech Silver Metal.

Getting Started Printing your Straight Track

To get started printing your straight track you will need Depronizes “straight_200mm.stl file. We found we could load 3 pieces of this track to be printed at one time, on a standard 220mm x 220mm 3D printer. Arranged them this way:

Printing in “two tone”

One of our members came up with this “two tone” process using our slicer of choice, Simplify3D. You can probably do this with other slicers out there, but we will be showing you how to do this using Simplify3D.

First, you need to figure out at what “height” you want to switch colors at. For us, we found the best place to switch colors for the straight track is a z height 2.98 millimeters. This finishes the top of the track ties, and just starts the rails:

Once this stopping point has been decided, it is time to get to work with the slicer. The solution to multi-color print with a single color FDM printer is simple. You need to break the print up into two files. But here is the trick: You need to tell the printer to “keep everything running” when it’s time to switch the filament before you begin you second print.

Using Simplify3D, you would do it this way:

• First open the file you want to slice (in this case the straight track). Then go into the process you have set up in Simplify3d

• Click on the “Advanced” tab. Then place a check mark in “Stop printing at height” checkbox. Enter the value 2.98 (That is our stopping point)

• Click on the “Scripts” tab. You will see various scripts that tell your printer what to do before it starts to print, when it’s done printing, and a few other functions. You want to select “Ending Scripts”. Here would normally be the “gcode” to tell you printer to go home and shut down the heaters (extruder, bed) and turn off the stepper motors. All we want in this ending script tab are the codes G1 X0 Y0. This simply tells your printer to go home for the x and y axis but leave the height alone and leave everything running. Note: Some printers with Marlin firmware require you to add one additional line of code to the script.

M0

M (zero) tells the printer to pause. If you don’t put this code in the script, the Marlin firmware could shut down your hot end (and bed) heaters.

• After you have made these changes, click on the “OK” button. To save the changes.

• Now, back in the processing section, make sure your process is still highlighted. On your computers keyboard press CTRL C (to copy the process) then press CTRL V (to create a copy of the process). You will now have two processes.

You want to select the second process and again click “Edit Process Settings”

• Click on the “Advanced” tab. Since this was a copy, you will have a checkbox in the “Stop printing at height” box. Remove that checkbox. Then place a check mark in “Start printing at height” checkbox. Enter the value 2.98 (That is the starting point for our second file)

We also recommend changing your infill setting to 100% for the top portion of the track, to make it as strong as possible.

• Click on the scripts tab. You want to select the ending script again. You can enter all your “shut down” values again, to turn the printer off when it is done.

• You also may want to adjust your “starting script” (things your printer would do when getting ready). Most people will want to completely remove any code in this box, depending on what type of printer you have.

When you are done with this, again, click on OK to save the changes to this second process.

Creating Your Two Gcode files for Tracks

With the processes saved, you can generate your two gcode files for the tracks this way in Simplify3D.

• Click “Prepare to Print”

• Select and highlight just the first process. Then click on OK.

• In your preview window, you would see just the first part of the track is ready to print if you did everything correctly, and you can save the gcode file.
• If things look good, save your toolpath to disk (the gcode). Give it a name such as track base or track 1 so that you can remember which file to print first and save it.

Then exit the preview mod. Time to go back and create the other file.

• Select the second process file and again, click on prepare to print

• When the process selection window comes up, select, and highlight only the second process, and click on OK.

• If you have done everything correctly, you should see the top half of your track suspended in midair, in the print preview window.

If you see this, save your second Gcode file. You are now ready to print! At this point all you need to do is: 1) print the first file with your first color. Your printer will park itself when done, stopping after the black layer:

If you used the M0 code, your printer may be displaying “paused”. Swap your filament before clearing the message. You will most likely have to press “resume”. As so as you do, some printers start “cooling down”. That is when you want to start your second file. The printer should pick up where it left off and give you a nice-looking set of straight tracks!

Printing the Curved tracks

We found that our GP38 likes the 30 degree radius R400 curves better than the sharper ones. So, in Depronize’s file, locate the file “track_curve_r400_30.deg.stl”. Two of these curves will just fit on a standard 220mm x 220mm printer bed like this:

Rinse and Repeat

Just like you have already done with the straight track sections, your first printing process should stop at 2.98mm and the second should start there. If you left your slicer open, and just removed the straight pieces and added the curved ones, your heights are all set! All you need to do is make sure the processes are properly assigned to both (see Simplify3D documentation on this point).

Again, generate your first gcode file by selecting only the first process:

and you should see the bases printed only in your preview window:

Save the file (again, naming it something like curve base ) and move on to the second process, to create your rails:

Save the second file and you are again ready to print!

Number of Pieces to Print

Using the 30-degree radius curves you will need to print twelve curve sections to form a complete circle. Printing the straight sections will be based on your desired layout. We found that printing the track consumes very little filament, so plan on a big layout!

We hope you enjoyed this article on creating your own 3D printed track. If you have not already done so, be sure to check out our other articles on building a train, such as the GP38. Stay tuned as we will continue to explore building our train with the addition of a gondola!