Scattered along the thousand-mile route new railway yards were springing up, each one a constant hive of activity with wagons coming and going all hours of the day and night. And while the company made sure the workforce was well provisioned, since, as Harry King had told the Ankh-Morpork Times, railway workers seriously needed a good meal and a good sleep in a comfortable bed after a day of heavy labour, in the end whether or not the bed was warm or comfortable didn’t in fact really matter because a lad would sleep the moment he fell into it, just as soon as the former occupant, waving his billy can, had hurried off for his shift.

It was all about speed and occasionally pure machismo, or whatever it was called in the languages of trolls, goblins and golems and, of course, the real hard-core steel men from the mountains who fought amongst themselves over nothing.

Where the new line followed the course of the River Ankh as it narrowed towards its source high in the Ramtops, barges came up or down the river with wood for sleepers, iron ore, coal and other supplies. The smelters worked through the night casting rails and if you were lucky enough to be in the right place and sufficiently protected you could see them open their guts and spill the glowing liquid steel: dancing and living like a creature from the underworld. If you were not lucky and stood too close then quite probably you would end up in that underworld facing the deity of your choice.

And all was fuelled by money, money, money, eager investors turning gold into steel and coal in the hope that it would turn back into even more gold.

The company was building bunkers everywhere along the tracks and it truly came home to Moist that when it came to the railways the engines and carriages and so forth were just the show up front, the iron horse, which needed to be fuelled and watered. And all of this was done by people almost the same colour as the coal, momentarily spotted as you went past, and then forgotten. He knew, because he had attended all the meetings and listened, that running a railway was a lot of small puzzles which, if you opened them, presented you with another sequence, full of constraints, and lists of things that definitely had to be done before anything else could happen. In short, the railway was complexity on wheels. It was amazing that Mr Simnel’s sliding rule didn’t glow as red-hot as the furnaces he worked.