Legend has it, that a member of the local Madden family who were major shareholders in the Great Northern Railway visited Milan. While there, he visited a new railway engine shed constructed alongside a turntable. Impressed, the plans were copied and a replica built in Clones. Whatever the veracity of this story, this is a fine structure now surrounded by more modern industrial buildings. In plan, it is a section of a donut, built with a semicircular section.

It was built in 1926 of precast concrete and subsequently, a similar shed was also built in Portadown Co. Armagh by the GNR but since demolished. An attempt was made to demolish the one at Clones but the strength of the building resisted this attack.