Union Pacific Big Boy steam locomotive 4014 chugs into Salt Lake City on July 4, 2024. Spectators line the tracks and the pedestrian overpass to get a good look at this state of the art technology from 1941. The Big Boy steam locomotives are the largest ever built. Union Pacific had a fleet of 25 of these massive machines - just under 2 million pounds - can pull a train 5 miles long - 8000 horsepower - almost a half a city block long - 90 mph top speed - in use for regular service 1941- 1959. Seven were saved- this one 4014 was restored to operating condition. Bravo and thank you Union Pacific!