Hundreds of people gathered Wednesday morning to see a historic steam locomotive stop in Albert Lea. The train paused on its journey, which celebrates the transcontinental railroad's 150th anniversary, for photos and inspection by onlookers. - Sarah Kocher/Albert Lea Tribune

Big Boy No. 4014 traveled to Albert Lea from Mason City. It was intended to arrive at 9:15 a.m., but was 50 minutes late after a delay near Gordonsville due to another train on the one-track line. - Sarah Kocher/Albert Lea Tribune

The locomotive engineer waved at onlookers as the Big Boy slowly pulled out of the station after its 40-minute stop. - Sarah Kocher/Albert Lea Tribune

Between approximately 300 and 400 people turned up at the Albert Lea depot southeast of Main Street to see Big Boy, Union Pacific's steam locomotive No. 4014. - Sarah Kocher/Albert Lea Tribune

During its time at the depot, the train occassionally blew its distinctive whistle and rang its bell as it inched up the tracks for onlookers to see. - Sarah Kocher/Albert Lea Tribune

People wait outside the depot for the historic locomotive to arrive Wednesday morning. - Sarah Kocher/Albert Lea Tribune

While Big Boy No. 4014 used to run on coal, it has been converted to run on No. 5 oil. The locomotive's water capacity is 24,000 gallons. That water is heated into steam, which is piped into a cylinder and causes a piston to reciprocate, or move in and out. That piston motion powers the locomotive. The heat from the locomotive can be felt standing next to it. - Sarah Kocher/Albert Lea Tribune

Steam locomotive No. 4014 departs Albert Lea on its way to the next stop in Owatonna. The train was slated to spend the night at the St. Paul Union Depot. - Sarah Kocher/Albert Lea Tribune

Big Boy No. 4014 was retired in 1961, after 20 years and 1,031,205 miles traveled. It was reacquired from a museum in California in 2013, relocated back to Cheyenne, Wyoming — where the locomotive normally operated — and restored. - Sarah Kocher/Albert Lea Tribune

Albert Lea residents and visitors alike wait for the Union Pacific's Big Boy No. 4014, one of 25 built exclusively for Union Pacific Railroad. According to Union Pacific, the locomotive is 132 feet long and weighs 1.2 million pounds. - Sarah Kocher/Albert Lea Tribune