Following on from the LEGO train bogies experiment, we can use to approximate the relationship between bogie pivot points (in LDUs), and the bogie rotation on a curved track.

This is relevant to me, as it sets design constraints for LEGO train car bases and bodgie sets

Trailer base and small bogies

Several recent LEGO train models use this pattern.
The base is 32 studs long.
On a sharp curve, small bogies get close to the base but don't touch.

An increasingly common train car design uses two trailer bases connected to small bogies. I wanted to use them for my Tangara, but This base only works with small, simple bogies. Anything wider (or decorated) won't fit.

Custom drop-floor base

The LEGO Tangara uses decorated bogies of various sizes, so I need to use a custom base that can support them well. Keeping the above equation in mind, I ended up with the following.

This base has the same bogie pivot points.
The base is 30 studs long.
Decorated medium bogies don't touch the base.

This also works for decorated large bogies (like motor bogies).

This base has the same bogie pivot points.
The base is 34 studs long, including the nose.
Decorated motor bogies also don't touch the base.

If you have any feedback or questions related to this article, please reply to my post on Mastodon. This article is part of the LEGO set.