Big Boy 4014 rolled into Union Station on Monday evening, thrilling fans with its steam release and making them cover their ears as it blared its horn.
The vintage 1941 locomotive measures 133 feet long and weighs more than a million pounds.
![Visitors at Union Station cover their ears as Big Boy number 4014 blows its horn while parking at the rail yard.](https://npr.brightspotcdn.com/dims4/default/b9a0429/2147483647/strip/true/crop/1600x1068+0+0/resize/880x587!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2Fd0%2F5c%2Fd32fca93417dba564455bafd9158%2Fbig-boy-118.jpg)
Fred Overton, from Leawood, was one of hundreds of visitors who wanted to see the historic engine make a stop in Kansas City.
"It's wonderful. It's so good to see a steam train," he said. "It gets your attention. You just don't see many vehicles like that. When you get a chance to, you're looking at history."
![Big Boy demonstrates an intricate display of engineering marvel in the vintage 1941 locomotive that logged 20 years of service.](https://npr.brightspotcdn.com/dims4/default/b228eed/2147483647/strip/true/crop/1600x1067+0+0/resize/880x587!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2Fe4%2F78%2Fadd2b57f448d8f2270643cd6a737%2Fbig-boy-320.jpg)
Big Boy 4014 was put into service in 1941 to carry loads between Ogden, Utah, and Cheyenne, Wyoming. It was retired in 1961 after logging more than 1 million miles.
Number 4014 is only one of eight remaining of its kind, but it is the only one still operating.
![The engineers of Big Boy delight fans Monday by releasing steam as it settles on its resting place at Union Station.](https://npr.brightspotcdn.com/dims4/default/4cad644/2147483647/strip/true/crop/1600x1067+0+0/resize/880x587!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2F7d%2F86%2F9d2db0f44874a1a59800bfcf6217%2Fbig-boy-413.jpg)
Henry Ward, a recently retired Union Pacific employee, was one of the hundreds of people milling around waiting for the arrival of the steam engine. He was carrying a digital camera with a telephoto lens for the occasion. Even he was impressed with Big Boy.
"A regular train, I see all those every day. But these other steam engines that come out. They've got a lot of history behind them," Ward said. "There's not that many of them here."
![Visitors to Union Station marvel at Big Boy 4014 as it rolls through the rail yards on its initial arrival to Kansas City on Monday.](https://npr.brightspotcdn.com/dims4/default/5644029/2147483647/strip/true/crop/1600x1068+0+0/resize/880x587!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2F66%2Ffa%2F96697a274492ab25b022c7da7c99%2Fbig-boy-60.jpg)
The engine rolled into Union Station around 7 p.m. Monday, but continued down the tracks and out of sight — to the confusion of many waiting visitors.
It had to move down the tracks to allow other trains to pass before it backed up and returned to Union Station to the spot where it will stay so visitors can get a glimpse of it before it leaves Wednesday morning.
![Hundreds of people crowded into the grounds around Union Station to watch the world's largest operating steam engine roll into town Monday evening.](https://npr.brightspotcdn.com/dims4/default/60cd359/2147483647/strip/true/crop/1600x1068+0+0/resize/880x587!/quality/90/?url=http%3A%2F%2Fnpr-brightspot.s3.amazonaws.com%2F2d%2F17%2F80c03a454907a33c50cb9aa72ae5%2Fbig-boy-201.jpg)
Union Pacific completed restoration of the train in 2019 to celebrate the 150th anniversary of the completion of the transcontinental railroad. When Big Boy is not traveling around the country, it rests in Cheyenne, Wyoming.