Are there any overpasses less than 13 feet high

Some parts of the track are over 13 ft

I wouldn't think so. The steam engine itself is very tall. But high up there are no roads over.

Do you mean on the road to get there, or do you mean on the track itself?

The railway is built over fairly rough ground, so the track is sometimes only a few feet off the ground, but at other times it is well over 13 feet