Atlas and Alfred were Mines Engines.
The mines engines, Atlas and Alfred were brought over from France to work on Sodor. They were bought by the Mid Sodor Railway to work at the Mines. However, Atlas was involved in an accident on her first day on Sodor. Because of this, Atlas' cab was removed. Altas was sold away in 1936, later returned to Mid Sodor Railway while Alfred was worn out by 1929 and was soon taken apart to be used as spare parts for Atlas.
Later on, when the Mid-Sodor closed, Miney and Alfred were abandoned on a small siding close by to Arlesdale. Later on, they were discovered by Bert, who contacted the Small Controller. Miney and Alfred were then sent to the Skarloey Railway.
When the two were restored, Miney was able to work properly, but Alfred couldn't; so he was sent to the Kirk Ronan Railway Museum.
The Mines Engines never appeared in any stories, but appeared on the Reverend W. Awdry's model layouts of the Mid Sodor. Originally there were two Mines Engines, but soon became one.
The mines engines are modelled on the Jouef Decauville 0-4-0PT.