The world's largest operating steam train is in Denver. Union Pacific's legendary Big Boy No. 4014 locomotive made a pit stop ...

The world's largest operating steam train is in Denver. Union Pacific's legendary Big Boy No. 4014 locomotive made a pit stop ...

Big Boy,” a 1.2 million-pound locomotive, is back in Colorado after being restored to the world’s largest operating steam ...

The world's largest steam locomotive chugged through Colorado Thursday as part of its limited summer tour. Here are some of ...

Big Boy, all 1.2 million pounds of it, came rolling into Houston Friday afternoon. The four-cylinder steam engine was built in 1941, and is the last of 25 similar models still in existence.