better get down and get to sleep. You boys can put the fire out - tread out all the embers.'

Roger woke him, and handed him the shot-gun which the sentry kept. He got to his feet, feeling stiff, and rubbed his legs with his hands. The moon was up; its light gleamed on the nearby river, and threw shadows from the small group of huddled figures.

'Seasonably warm,' Roger said, 'thank God.'

'Anything to report?'

'What would there be, but ghosts?'

'Any ghosts, then?'

'A brief trace of an apparition - the corniest of them all.' John looked at him. 'The ghost train. I thought I heard it hooting in the distance, and for about ten minutes afterwards I could have sworn I heard its distant roar.'

'Could be a train,' John said. 'If there are any capable of being manned, and anyone capable of manning one, they might try a night journey. But I think it's a bit unlikely, taken all round.'

'I prefer to think of it as a ghost train. Heavily laden with the substantial ghosts of Dalesmen going to market, or trucks of ghostly coal or insubstantial metal ingots, crossing the Pennines. I've been thinking - how long do you think railway lines will be recognisable as railway lines? Twenty years - thirty? And how long will people remember that there were such things, once upon a time? Shall we tell fairy stories to our great-grandchildren about the metal monsters that ate coal and breathed out smoke?'

'Go to sleep,' John said. 'There'll be time enough to think about your great-grandchildren.'

'Ghosts,' Roger said. 'I see ghosts all round me tonight.

The ghosts of my remote descendants, painted with woad.'

John made no reply, but climbed up the embankment