Then his lordship said, ‘Can it really be possible?’

And in the squirrel cage of Moist’s mind, he thought, Can it? Can it really? It must be more than twelve hundred miles! It takes well over two weeks by coach and that’s if you don’t get hijacked, but who was going to try to hijack an armoured train? The engine would be wanting water frequently and is it possible that it could carry enough coal for the whole journey? The numbers rolled in his head. Stopping places, troughs for water, mountains, gorges, bridges, marsh land … So many things, any one of which could scupper the project …

But going to Uberwald would mean passing through so many other places on the way and all of them could be opportunities to make money. The demons of critical path analysis swarmed around his brain. There was always something that you had to do before you could do the thing you wanted to do and even then you might get it wrong.

To Vetinari he said cheerily, ‘Well, sir, I don’t see why not. And, of course, for such a long journey it should be possible to sleep on the train and for heads of state to occupy a complete suite of carriages, if not the whole train. Surely that could be arranged?’ Moist held his breath.

After a few seconds his lordship said, ‘That would be appropriate, but, Mister Lipwig, I am not entirely bribed. The train must prove itself both financially and mechanically. However, I look forward to its success. It seems, Mister Lipwig, that you are using your extra-cheery voice and so once again you find yourself in your own chosen environment, that being the centre of everything. But tell me: where do you think will be the destination of the first commercial train? Quirm?’

‘Actually, sir, that has been discussed and it looks as if it’s going to be Sto Lat, because that’s where Mister Simnel has his machine tools and a large stock of materials that he would need to transport to Ankh-Morpork. Besides, that place is a nexus for the Sto Plains, and nexus means—’

Lord Vetinari raised a hand and said, ‘Thank you, Mister Lipwig. I do know what a nexus is.’

Moist smiled and headed for the door, showing his panic only on the inside, and as his hand reached the doorknob Vetinari’s voice behind him said, ‘Mister Lipwig, you surely realize that a thoughtful prince, a prince who wishes to keep his throne for some time and is shrewd in the ways of people, would not travel in a thrilling armoured train … He would put somebody else on that train, somebody expendable, having himself travelled the previous day in a suitable disguise. After all, there are such things as very, very large boulders, and most definitely there are a great many spies. But I shall consider your idea. It has a beguiling ring to it.’

Over the next few weeks more and more people heard about Iron Girder and even larger crowds passed through Ankh-Morpork to see the new marvel of the age, including delegates, ambassadors and representatives from most of the towns across the Sto Plains. And, of course, there were the other artificers and freelance tinkerers, inspecting everything they could see and trying to find out everything they could about what it was they weren’t being allowed to see.