Train fans cheered Big Boy across Missouri, celebrating the last and biggest of its kind

The legendary Union Pacific Big Boy No. 4014 came through St. Louis this week, drawing big crowds along the route to see the world’s largest operating steam train. Aiden Drohr, a tour guide and train operator at the National Museum of Transportation, talks about the history of this massive train, why it’s gained such popularity and spending a day “chasing” the Big Boy across the region.