Happily, I didn't hear the comment but it was the usual one about the catenary.
He stood there, supporting his chin on his hand, and his elbow on the other hand; looked around the layout then turned to go, muttering, 'should be working off the overhead wires'.......and walked off !
My fellow operator - a P4 Cornwall steam man - was livid !! I didn't get the chance to ask our friend about his armchair
Correction substituting 'hear' for 'here' - Grammar school lad as well !!