Stacking Block Toy Train MK3

This is more a "homage" than a direct remix of Caj's inspirational Pull Toy Train.Update:After extensive field testing (thank you Harper, Cora, and Brenna) I discovered that when a child puts their weight on the car this puts stress perfectly in line with both the printed layers and the weakest area of the axle and causes it to break. This appears to be the primary failure mechanism and results in either threaded stubs stuck in the wheels--or worse--a small chunk of free plastic just small enough to be a choking hazard.I STRONGLY ENCOURAGE EVERYONE TO REPLACE THEIR AXLES IMMEDIATELYThe new AxleV2 includes a hollow for a 5x60mm dowel pin. This insert makes the axle all but indestructible. Specifically, I used these from Amazon.I suggest you split the part and print it in two long halves and superglue them around the pin. However, you can also insert a pause at the end of the pocket and insert the pin during the print.I am leaving the original axle up in case someone is using