Hunt Evidence Along the Line
Look for dated dispatch and arrival markings that match the line, auxiliary markings identifying transit offices, and endorsements referencing trains, steamers, or roads. Supplement with timetables, route notices, or news clippings that corroborate schedules and service interruptions. When a winter storm delayed a pouch, or a bridge washout forced rerouting, document it through contemporary reports and align the postal trail with real-world disruptions.