popular ! Holmes on the Range Mysteries Ser.: On the Wrong Track by Steve Hockensmith

It might be 1893 and the current world may in full-swing, but cowboy Gustav "Old Red" Amlingmeyer is an old-fashioned kind of guy: he prefers a long trail ride even when a train could acquire him where he's going in one-tenth the time. His brother Otto ("Big Red"), on the other hand, wouldn't mind climbing down from his horse and onto a train once in a while if it'll give his saddle-sore rear end a rest. So when it's Old Red who insists they sign on to protect the luxurious Pacific Express, despite a generations-old Amlingmeyer family distrust of the farm-stealin', cattle-killin', money-grubbin' railroads, Big Red is flummoxed. But Old Red, tired of the cowpoke life, wants to take a stab at professional 'detectifying' just like his hero, Sherlock Holmes and guard jobs for the railroad are the only ones on offer.
Mystery
Westerns
Historical Fiction