When people think of steam trains they instantly have images of the British-built Flying Scotsman and Mallard but just across the Atlantic laid an absolute behemoth of an engine.

The Union Pacific Big Boy was a true giant of the US' railway network and was a vital cog in transporting coal across the nation. Originally the Big Boy was the name of Union Pacific Railroad's 4000-class articulated steam locomotives of which 25 were constructed in total. Created between 1941 and 1944 by the American Locomotive Company they were the only locomotive to have the 4-8-8-4 wheel arrangement with four-wheel leading truck for stability and to support the large firebox.

Like with all steam locomotives however the Big Boy was sadly usurped by the modern diesel and electric engines that patrol the US' railway network today. While the Amtrak services can take passengers to every corner of the country there is still a large number of people that keep the Big Boy close to their heart.

Early life

In 1941 the first batch of Big Boy engines were delivered with 20 being put to use in Wyoming, ferrying coal from mines owned by Union Pacific. There was a further five built throughout 1943 to help during the war in the early part of the 20th century.

While all the Big Boy engines ran on coal there was an experiment which saw Locomotive 4005 converted to burn oil but it was deemed not successful enough and the engine was converted back to coal.

Sadly, like with all famous steam engines, once the war was over and the price of coal and labour began to increase the Big Boys saw their days starting to be numbered. The final revenue train hauled by a Big Boy finished in July 1959 while the entire fleet was decommissioned and replaced by diesel engines by 1962.

Legacy and preservation

The Big Boys may have left the rails in a commercial sense but that is not where the story ends as from the 25 made eight were preserved. The 4004, 4005, 4006, 4012, 4014, 4017, 4018 and 4023 are currently on display at various museums across the country including the Forney Transportation Museum in Denver, Colorado and Holiday Park, Cheyenne, Wyoming.

One of the engines has been subject to a campaign to be fully restored. An article by the Los Angeles Times told the tales of the Big Boy 4014 which had been on display at the Los Angeles County Fairgrounds in Pomona, California. Union Pacific has now stepped in and brought the engine back to Wyoming after purchasing it from the RailGiants Train Museum.

Once it is in the northern part of the US it will undergo extensive restoration work from the railroad company's maintenance department. However, officials have conceded that bringing this behemoth back to running order will be no mean feat and that they would be undertaking a huge task.

However, Aaron Hunt, company spokesman, summed the project up by telling the news provider: "We’re really excited about the acquisition of the 2014 Big Boy."