Brian Floca started his 2014 Caldecott Medal–winner Locomotive thinking that he would do a book about how the steam engine operates. He wasn't sure in the beginning where it was going or where it would be set. "In asking those questions, I got to the Transcontinental Railroad," he said. "It then totally upended the book."
As he conducted his research, Floca made discoveries that shaped the course of the story line. He had thought of the crew as the through line, but on the Transcontinental Railroad, there's a change of crews. He followed the path that the train would have taken, which also altered the story. He had been planning to show the train approaching the Rockies, winding its way toward a wall of mountain. But he found that the tracks wind their way in at the gentlest slope, near Cheyenne, WY. "Almost everything that has to do with the landscape is indebted to that trip—even the endpaper elevation map," he explained in an interview for School Library Journal's Curriculum Connections.
Ultimately, Floca decided to focus on one family's journey cross-country. What would they have seen and whom would they have met along the way? Maps of the Transcontinental Railroad's terrain, diagrams of the steam engines, and vignettes of the towns the locomotive passed through add dimension and detail to an unforgettable journey.