Lego Train-Compatible Tanker Car

This is a tanker car that is compatible with Lego Trains and Train Tracks.

It has a magnetic coupler at each end that allows the magnet inside to flip to ensure proper polarity with adjacent coupler magnets. Insert one magnet into the slot of each of the two couplers. They are designed for a 10x2mm size button magnet. I ordered mine from Amazon "DIYMAG 120 Pcs 10x2 Premium Brushed Nickel Small Round Cylinder..." You may need to use a tool to push the magnet through the slot. It's intentionally designed to be tight to prevent the magnet from working its way back out. You can widen the slot, post-print, of course.
There are two options for the wheel trucks. The ones that end in "_Pin" use a 2mm x 45 mm stainless steel round shaft axle rod that can be found on Amazon. The ones that do not end in "_Pin" simply use M3 screws. The _Pin version has a lower rolling resistance, but in my opinion creates slightly more noise than the M3... not a lot though. The decision of which to use