They might not have been quite so relaxed had they known of the drama taking place up ahead on the footplate. Old Archie, pressed into service as an extra fireman, had passed out.
"Lift him up, lift him up!" said Tam the driver to his regular fireman Bert. "Hold his head out of the cab!"
Sure enough, the vapour clouds revived Archie in no time.
"Never fails," Tam said. "Steam of consciousness."