I've updated the original file , with a more detailed version, and a made a major technical change to the way the whole thing is put together.

Instead of using a separate model for each of the 20 frames of the animation. I've cut back the number of Collada models to 3 and used the kml to instance them in different ways.

The 3 Collada components are:

- the static A-frame support structure.

- the wheel, which I gradually rotate by changing the value in the tilt tag in every Time-Spanned element.

- a model of a single carriage, instanced 15 (or 30) times each frame. With changing latitude, longitude and altitude values.

File size is reduced from 3.8MB to a much more modest 268kB.

Loading time is increased slightly, but the effect as each element appears is kind of interesting - rather like a flourescent light coming on.