They were the iconic image of the American railways and now one has been brought back to life.

The Big Boy locomotives were some of the largest trains ever to grace the US' railway network, transporting freight all over the country. Now, the Big Boy No. 4014 has been given another run out after a painstaking restoration project, the Daily Mail reports. This Union Pacific model was responsible for transporting goods over the mountains of Wyoming and Utah until it was pulled from service over 50 years ago.

Now, the giant of the railways is back and has been put to work pulling excursion trains in California, drawing in enthusiasts from all over the US. It is one of just eight surviving Big Boys from the original 25 that were built by The American Locomotive Co in Schenectady, New York, between 1941 and 1944. Sadly 17 were scrapped once the Big Boys had been overtaken by the modern day diesel engines, which were deemed much more efficient than their steam-powered counterparts.

While their size is impressive, Big Boys are not lumbering locomotives as they were engineered to reach top speeds of 80mph. However, the railways of the US were not intended for the locomotives to reach this kind of speed. The return of the Big Boy No. 4014 has taken many by surprise, including Jim Wrinn, editor of Trains, a magazine that covers the railroad industry.

Mr Wrinn was quoted by the news provider as saying: "It's sort of like going and finding the Titanic or something that's just very elusive, nothing that we ever thought would happen. Something that's so large and powerful and magnificent, we didn't think any of them would ever come back."

The Big Boy No. 4014 has now been relocated from its previous museum home to a Union Pacific shop in Colton, California where a crew is preparing to tow it to Cheyenne, crossing Utah and Wyoming. It is due to arrive tomorrow (May 8th).