[1] The railway was built between 1873 and 1875 by the British Rio Tinto Company Limited (RTC),[2] that sought to provide maritime access to the minerals extracted from ore deposits in the Riotinto-Nerva mining basin.

[5] After several years the abandoned infrastructure was subject to looting, so in the late 1980s action was taken to recover the historic railway line and return it to service.

[10] The acquisition of the mines was accompanied by a state concession to build a railway line to connect them with the port of Huelva and thus allow the transport of the extracted minerals to the coast.

The most complicated part of the project was between the Riotinto mines and the municipality of Niebla, a section where the route had to run parallel to the course of the Tinto River.

[13] The slag resulting from the ancient mining works carried out in Roman times was used as track ballast — because it was abundant in the Riotinto basin.

Construction was completed three months ahead of schedule and also at a budget cost of 767,190 pounds sterling at the time, a figure lower than expected.

Some branches were later added to the mainline to link it with the area's ore deposits and industrial facilities, a network totalling almost 360 km (220 mi).

The track started at the company's mining complex and ran parallel to the course of the Tinto River, until it reached the port of Huelva.

[21] In 1896, with the Seville-Huelva track already operational, a junction was built at Las Mallas railway station to carry out transfers between the two lines.

[22] In its early days rail traffic was irregular, since it depended on whether there were ships docked at the port to load ore. Another problem was locomotives getting worn out after many trips between Riotinto and Huelva due to the steep gradient between them.

[24] It is noteworthy that the start of operations of the Riotinto railway allowed the arrival of certain products from the coastal area and the countryside to the mining basin.

In addition to occasional trips to Huelva, RTC employees and their families also used the train in summer to travel to the company's beach in Punta Umbría[30] Railway traffic was affected by the strikes of 1913 and 1920, that paralyzed activity in the Riotinto-Nerva mining basin.

[31] The growth in traffic experienced by the railway in the early 20th century led the company to introduce a series of modifications to allow dual traction, making it possible for larger convoys to circulate.

There was a project to provide electricity to the general railway in order to save costs, although it was not implemented due to the outbreak of the First World War.

In order to introduce new engine material, the RTC had acquired new Mogul type steam locomotives, colloquially known as "Gildas", which arrived in Spain in 1954.

[37] Although the use of steam locomotives prevailed for most of the railway's existence, diesel traction would eventually be introduced in an attempt to modernize the fleet.

[42] During its final years, the railway traffic experienced such a decline that its exploitation ceased to be economically profitable for the owning company.

After the closure of the line, the facilities were abandoned and underwent uncontrolled dismantling, affecting both the railway tracks and the rolling stock parked in the locomotive depot at Zarandas.

[44] Many stations on the line were seriously deteriorated, while the historic facilities of Río Tinto-Estación and Huelva ended up disappearing for the most part after being dismantled.

[48] Following these postulates, the recovery of the rolling stock and infrastructure was carried out, which included the restoration of the tracks and the rehabilitation of stations such as Zarandas-Naya or Los Frailes.

[50] A small section between Talleres Mina and Zarandas was initially reopened for service; in February 1997, the operating track was extended to Los Frailes station.

[51] From the historical rolling stock that was recovered during those years — including two steam locomotives — the Tourist Mining Train was formed, which offers recreational services along the old railway route.

[Note 2][55][56] Among all of them, the Río Tinto-Estación complex stood out, which constituted an important railway junction where the tracks that went to Nerva and Zalamea la Real converged.

[23] Currently, only a section of about 11 kilometers between the stations of Talleres Mina and Los Frailes remains operational, while the main railway facilities of the line are located in the complex of Zarandas-Naya.