Like all mining railways, this line has a very modest history. The rich deposits of iron in the hills near San Nicolás del Puerto prompted some astute British investors (as was so often the case back then) to acquire the mining rights over the area in the late 19th century. In order to take the ore to market, they built a railway along the Rivera de Huéznar river to link up to a nearby broad gauge line 15 km downstream.
Work on this spur line was started and completed in 1895, and unlike other mining railways it was built in broad gauge. This was an advantage when it came to operating the line, which was first transferred to MZA (standing for Madrid, Zaragoza and Alicante) and later to Renfe, owners of the main line further down the valley.
No passengers were ever carried nor were any goods other than the iron ore from the mine, although there was a great deal of interest from the towns and villages through which the line passed and a number of attempts were made to introduce other services. Finally, in 1970, a circular to Renfe employees announced the closure of services on the Río Huéznar to Cerro del Hierro spur line. The company informed that the tracks and other railway infrastructure would be left in place for the time being pending a possible revival of the mining operations that the spur line served. Such a revival never occurred