Murder at Deviation Junction — Andrew Martin

From the author of The Necropolis Railway, The Blackpool Highflyer, and The Lost Luggage Porter comes another thrilling mystery featuring railway detective Jim Stringer. It is winter 1909, and Jim desperately needs his anticipated New Year's promotion in order to pay for a nurse for his ailing son.
Jumping at any opportunity to impress his supervisor, Jim agrees to investigate a standard assault in a nearby town. But when his train home hits a snowdrift and a body is discovered buried in the snow, Jim finds himself tracking another dangerous killer. Soon he is on a mad chase to find the suspect, trailing him to the furnaces of Ironopolis and across the country on a dangerous ride to the Highlands. As pursuer becomes pursued, Jim begins to doubt he will ever get his promotion -- or that he will survive this case at all.