The Scottish verses were an adaptation by Arthur Lloyd, "made by permission", of Sam Cowell's original Railway Porter. Lloyd, it seems, was always conscientious in crediting Cowell. The song, after all, was his first big break.

"Arthur Lloyd's first music hall engagement was with Mr James Shearer at the old Whitebait Music Hall, Glasgow, when he was engaged at a salary of £4 a week, and made a big success with a song of Sam Cowell's called The Railway Porter, which that performer permitted him to make into a Scottish ditty."

- 'Arthur Lloyd - A Reminiscence' in The Era, 23 July 1904. Quoted at  http://website.lineone.net/~kingk_lloyd/Lloyd/Table%20of%20contents/Doc02.htm

Various past threads here have already quoted the Scottish form; a Forum search should find them quite easily. In one, it's suggested that it may have been based on George Grossmith's The Muddle Muddle Porter, but that seems unlikely. The songs have very little in common beyond general subject matter.

"Billy Weeks" is our main expert on Music Hall, I think, so I hope he spots this thread. Steve Gardham may also know about it; he looks in here only rarely, but I'll ask him.