weerover: Thanks a million! With your assistance: the BBC America Shop Index of Traditional Scottish songs gives these lyrics:

WILLIE LEE

Oh, I am a railway porter and my name is Willie Lee,
You can search around the country frae Dumbarton tae Dundee,
I'm the most important person that you're ever like tae see
And my duty is tae tell ye whaur ye chinge fur..
Ye change fur....

Chorus: Auchterclochter, cuddlemadochter, Crieff or Callercoats,
Land's End tae John o' Groats, Beecham's Pills or Quaker Oats.
Ye chinge fur Ecclefechan, Aiberdeen an' a' the stations in between
Unless ye want tae gang tae Tobermory.

Oh, at Auchterclochter junction if you're ever like tae be,
Just pop your head frae the windae and you're sure tae notice me,
I'm the most important person that you're ever like tae see
And my duty is tae tell ye whaur ye chinge fur ...
Ye change fur....

Ae day at Auchterclochter junction, oh I wis filled wi' pride!
The royal train drew in and when I looked inside,
I saw Her Majesty, Lizzie, the Queen and the Duke wis by her side
And they asked me a' the stations that ye chinge fur . . .
Ah telt them...

Auchterclochter, cuddlemadochter, Crieff or Callercoats
Land's End tae John o' Groats, Beecham's Pills or Quaker Oats
Ye chinge fur Clachnacudden, Sands o'Budden and then ye buy a big mealy pudden
Tae eat until ye gang tae Tobermory,
Tae eat until ye gang tae Tobermory.

So far as I can ascertain on line, it really is traditional. If you have better lyrics than these, pse add!