Vanished Gold. Jake Lazarus Western Mysteries, #1

How can you solve the mystery of an impossible train robbery? That's what Jake Lazarus has to find out. His oldest friend, to whom he owes his very life, needs his help desperately. And Jake Lazarus is determined to provide that help, however hard it gets. But first he had to discover what a missing Pennington Detective agent, a locked-on-the-inside train car containing three murdered bodies, a missing cache of gold bars, a traveling preacher who's more than he seems, and an actor between roles might have to do with the robbery.
If anything. More used to tracking rustlers and bandits across the plains, what does Jake know about big cities and rich railroad owners, tunnels blasted through mountains and stolen bullion? And the biggest mystery of all? Jake's not entirely sure who he is himself.