[Falcorian]

They prefer to have them at the end because:

1. You don't want these cars to get banged around a lot and maybe have their weight change.

2. So you put them at the very end where they take the least wear and tear.

3. But they're not allowed to be the last car because they often don't have brakes.

So you put them as the second-to-last car.

This answer based on combining two of the captions from the page:

> Always the "Second to Last Car in the Train"

> Andrew B Baird: No brakes so it is not permissible to be the last car.

And

> The scale cars are now more robust? I notice that this car is not on the end of the train.