Union Pacific Big Boy, the largest, most powerful steam locomotive in the world, tours the U.S.

Train lovers flock to see “Big Boy,” the world’s biggest steam locomotive

Union Pacific's Big Boy No. 4014, the world's largest operating Steam locomotive in Struthers, Ohio.

Union Pacific Big Boy 4014 crosses the bridge at Letchworth State park in New York.

Kato USA n scale Union Pacific Railroad Big Boy 4014 excursion Model Trains 1:160 gauge railroad FEF

Union Pacific Big Boy 4014 giant meet giant

History in Motion: Big Boy 4014's Journey Across America