M. Le Marquis des Aix-En-Pains owns extensive vineyards in Quirm which straddle the proposed line of the new railway form Ankh-Morpork to Quirm. He is a personne des affaires who has much influence in both Quirm and Ankh-Morpork, a destination for his fine wines and spirits distilled therefrom. He therefore has a vested interest in getting his produce quickly and reliably and within the bounds of accepted ullage to where the money is. He advises Moist von Lipwig on a preferred route that will not cut into his vineyards and advises him on local law and custom, pointing out that as he is by default Marquis of the Maquis, nobody will object too much if this is where the way is made permanent. He warns Moist that the maquis country has two sets of residents: the goblins who live there, and the bandits who prey on them. They work out a scheme to pacify the wilderness, and zut alors! - the railway eventually reaches Quirm.