Riding the Rails by Amelia C. Adams

Mercy Davis, left alone in the world when her mother passed away, must leave her home in the goldfields of California and create a new life for herself. With no money whatsoever and no friends to ask for help, she takes a risk and hops aboard an eastward-bound train, heading for Denver, where she believes she will start afresh.
Heston Granger leads a simple life working at the railroad station. Everything in his world is predictable and routine until he opens the door to the stock car and discovers not only a dozen cows without an owner, but a stowaway who happens to be a young woman. As he learns her story, he finds himself eager to help her reach for her dreams – and perhaps a forgetful angel is just who they need to give them a little boost in the right direction.