Richard J. wrote:

I fail to see what the story tells you about GFF's skills as a
railwayman. Care to explain?

It doesn't tell you anything about those skills directly. But only a
supreme raconteur (and, in this context, that is a euphemism for
bull****ter) would feel confident in spouting such garbage. So, in the
field of the raconteur/bull****ter, he was supreme. As a railwayman,
he wasn't.