The Norfolk and Western Class O-18 was the sole example of an 0-4-4 Tank Engine built by the Mason Machine Works for the Norfolk and Western Railway on their yard switching duties as a switcher.
History[]
In the 1880s, the Norfolk and Western Railway needed another tank engine for use on their yard switching duties. They had two examples of the Class B 0-4-4T and so the Mason Machine Works had took No. 96 to their works and converted/rebuilt it into what had later became the O-18, No. 96 was constructed in 1883, the same year it was first constructed as a Class B, leaving No. 97 as a Class B.
It was retired from active service on its yard switching duties and it was sadly scrapped, with No. 97 as a Class B following No. 96 to oblivion later on which would render the Class B extinct.