Brio compatible train with integrated whistle!

Enjoy playing with a bio train, that can also function as a whistle. The whistle consists of two notes, and sounds a lot like a train, without being annoyingly loud. I tested this train on a number of different track configurations, both in a “tow” and “push” configuration, and through that testing developed the truck rotation limiters, which allow the trucks to independently traverse without over-rotation.

Printing
The print was done on a Bambu X1Carbon, using Sunlu “purple” AMS filament. I'd encourage folks to use the print profile provided, since the tolerances are known to work on it.

Additional parts (optional):
https://www.amazon.com/gp/product/B000BPGSSW/ (pins used to secure in the magnets, make for a rounded surface)
https://www.amazon.com/gp/product/B09LYWGGFR/ (magnets used)

https://www.amazon.com/gp/product/B0B8SWWL58/ (glue used to secure truck pins to main truck body)

This train design is compatible with magnets and pins, to allow it to connect to other trains.

Assembly:
There are a number of pins in this print used to connect the pieces, but no mechanical screws are used. The tolerance on the pins is close enough that you can slide them together, and they will stay put for display and light use. If you want to further secure them, I used a soldering iron to melt the axles pins together underneath the truck, and you can to this through the window to the axles underneath the train. The pin between the trucks and the train body is pretty tight, but I used one drop of Cyanoacrylate glue to make sure they aren't going anywhere.

Finally, if you want to add magnets, the trucks can accept 10x5-4mm Neodymium magnets, secured via laundry pins. (Link above) These aren't strictly needed, but do provide a compatible interface to make this the locomotive for a larger train.

Attribution:
This design was inspired by a number of existing train and whistle concepts online, including but not limited to:

https://makerworld.com/en/models/49375
https://makerworld.com/en/models/434352

However, I built all these parts myself using CAD.