Historic Big Boy, world's largest operating steam locomotive, rolls through Pennsylvania for first time

Thousands of people gathered on Tuesday to watch the world's largest operating steam locomotive roll through Pennsylvania for the first time as part of a coast-to-coast tour celebrating America's 250th anniversary. 

The Lake Shore Railway Museum in North East, Erie County, said more than 4,250 people showed up at its property on Tuesday to see the legendary Union Pacific Big Boy No. 4014, and about 1,000 more people gathered near the tracks. 

Described as the "Elvis Presley" of steam locomotives, Big Boy is making its first trip across the Mississippi River and into the Ohio Valley for the first time since it was built in Schenectady, New York, and delivered to Union Pacific Railroad in 1941. 

To celebrate America's 250th birthday, the locomotive is crossing its way through the Norfolk Southern network, and it will be back in Pennsylvania to celebrate the Fourth of July in Philadelphia. It'll roll through western Pennsylvania in mid-July, making stops in Leetsdale and Conway. 

Stretching 133 feet long and weighing 1.2 million pounds, 25 Big Boys were commissioned to haul heavy equipment during World War II, Union Pacific says. No. 4104 was retired at the end of 1961 after racking up more than 1 million miles. It returned to service in 2019 to celebrate the 150th anniversary of the Transcontinental Railroad's completion. 

The seven other Big Boys are on display, including one in Scranton, Pennsylvania. 

The coast-to-coast tour will wrap up at the end of July after Big Boy makes its way through a total of 14 states.