Terry Pratchett 
Raising Steam 
(Discworld novel 40)

”The world lives between those who say it cannot be done and those who say that it can . . . it”s just a matter of thinking creatively.”
Moist von Lipwig is a con man turned civil servant. As head of the Royal Bank and Post Office of Ankh-Morpork, he doesn”t really want or need another job. But when the Patrician Lord Vetinari gives you a task, you do it or suffer the consequences. In Moist”s case, death.
A brand-new invention has come to the city: a steam locomotive named Iron Girder, to be precise. With the railway”s introduction and rapid expansion, Vetinari enlists Moist to represent the government and keep things on track.
But as with all new technology, some people have objections, and Moist will have to use every trick in his arsenal to keep the trains running . . .
”The most serious of comedies, the most relevant and real of fantasies” Independent
Raising Steam is the third and final book in the Moist von Lipwig series, but the Discworld novels can be read in any order.