‘What’s remuneration?’ said the little tinker.

Moist said, ‘You’ll find out.’

As Iron Girder struck out for Slake, the gnomes lined up and waved tiny little handkerchiefs until long after the train was out of sight.

Fishing for carp in Lake Overshot that afternoon, Mr Geoffrey Indigo was quietly surprised when the water in the lake simply disappeared in a certain amount of bubbling, leaving some gasping fish, startled frogs and a rather attractive nymph, who was very angry and spat at him as if it was his fault. But the man who had written that well-known book Out with my Flies in All Weathers kept his calm and made a note to mention this phenomenon at the next meeting of the Overshot Fishing Society.

As he meticulously cleaned his gear and generally tidied up, he heard a liquid noise and was surprised for a second time to see that the hole in the landscape was now refilling with water. He watched amazed as the nymph spat at him again, leaving him feeling somewhat wronged. And on the way home, squelching a little, he wondered if anyone would believe him.

When he told his wife later about the strange day, she snorted.

‘Geoffrey, you really shouldn’t take your brandy flask with you!’

‘I didn’t take it with me,’ he protested. ‘It’s still on the sideboard, where it always is!’

‘Then just don’t tell anybody,’ his wife concluded. ‘People will think you’re strange and we can’t have that.’

Geoffrey, the least strange person in the world, except possibly when it came to talking about fish, decided not to say anything. After all, you didn’t want to become a laughing stock …

Moist was starting to worry about Dick Simnel and his band of overworked engineers. What sleep they got was in sleeping bags, curled up on carriage seats, eating but not eating well, just driven by their watches and their desire to keep the train going. If you met them away from the cab, their conversation was about gears and wheels and timings, but it was clear to Moist that they were frazzled after days of living on the footplate and wrestling their locomotives through various little tantrums.

And so he confronted Mr Simnel, saying, ‘Surely we can afford to slacken pace a little and let you and your lads get your heads down for a bit? As far as I can see, we’re well on schedule.’

And he detected in Dick’s eyes not madness but something else more subtle. He was sure it had no name. It seemed to be a sort of hunger for anything that was new and above all for proving that something could be refined to the point of perfection and kept there. In the goblins this was endemic, although it didn’t seem to do them much harm. Humans, apparently, were another matter.

‘People are going to die if we push them any further,’ he said to Dick. ‘You lot would rather work than sleep! I swear, sometimes you seem to be as mechanical as Iron Girder, and that’s not right, you have to … chill, get laid back before you are laid-back and laid down for ever.’