Thought I'd chime in and say your fine, just ignore them. There's a certain segment of men that are just like that, most likely others at your job have commented on how cool you are to be commuting like that. This will enrage this demographic - "Fing Punks" - so that they must talk as much trash as possible.

Don't confront them, that's what they want. They'll never directly talk to you, I promise. They have no sense of shame, and are huge hypocrites.

A saying I once heard - "People that are uninteresting talk about others"

Sincerely, a guy that's worked in manufacturing and construction, that deals with this all the time