Bottlenecks, Side Quests, and the Calculus of Historical Research

When I was researching my dissertation, I came across an intriguing snippet in an otherwise boring, 900-page government document: a four-page table showing how long it took mail to travel by railway between roughly 130 US cities and twelve major railroad hubs in 1882. This set my wheels spinning: what if I could use this to create a nationwide map of how fast information traveled between different…