Serón, Sierra Filabres Iron Ore, & Gillman's Water Solution

The terrain here changes dramatically. Serón itself is nestled directly on the northern slopes of the Sierra at an elevation of over 750 metres. The journey is a gradual but definite ascent, transforming the landscape from an agricultural valley into a wilder, rugged, and more forested mountain environment.

The GSSR had initially relied on assayers who promised abundant, soft water along the route, painting a picture of a veritable Garden of Eden. The reality, however, was a semi-arid zone with little water, and what was available was incredibly hard, packed with minerals that crystalized inside the locomotives' pipes and boilers.

From the start, engines were constantly out of action with calcified tubes. The constant need for repair meant that GSSR drivers and firemen became unofficial experts in boiler maintenance. The problem was dangerous, too. In September 1907, a boiler explosion on Engine No. 2, the LORCA, killed both the driver and the fireman—likely because the pressure release valve had clogged with limescale.

The company's saviour was Gustave Gillman, the GSSR's resident genius and eventual general manager. He found a source of soft water in the Bacarese River, which carried snowmelt down from the Sierra de Bacarese. Despite being tied up in centuries-old legal disputes, Gillman persevered. In August 1911, after sinking a well and installing a steam pump, soft water finally flowed to the Tíjola tanks. From there, a new pipeline supplied water downhill to all the stations in the valley, providing a lasting solution to the plague of scale and leaky boilers.

The logistical challenge of getting iron ore from the high, remote mines—up to 17 kilometres away—down to the railway line was monumental. The solution was an extensive system of aerial cableways built by companies like Ropeways Ltd. and Pöhlig.

The most significant operation centred on the Las Menas Mines, located in the Sierra Bacarese. At its peak, the adjacent village was a bustling town of 2,900 people with a school, hospital, and even a theatre. Ore was transported via cableway directly to the railway. Today, Las Menas is a dramatic ghost town, a stark reminder of the mining boom's rise and fall.

To handle the immense traffic, the GSSR built massive loading facilities, known as cargaderos. The Cargadero de los Zoilos at Serón, and later the much larger Los Canos cargadero a few kilometres down the line, were equipped with huge hoppers capable of storing tens of thousands of tons of ore.

The loading process was a complex feat of engineering: the cableway buckets would empty into the hoppers, and then trains of specialized wagons were shunted beneath the hoppers and loaded via controlled chutes. At Los Canos, because the station lacked a turntable, the locomotive would have to unhitch, proceed to Serón to be turned around, and then return to pick up its loaded train for the journey to the port.

When the mining industry declined and the railway finally closed in 1985, the town of Serón, like many along the line, had to find a new identity. It successfully reinvented itself by focusing on its natural beauty, restoring its 13th-century castle, and building on its traditional cured meats industry—famous for Jamones de Serón—to become a popular rural tourism and agri-food centre. Today, the line between Purchena and Serón, with its striking bridges and dramatic ascents, forms a completed section of the Vía Verde del Almanzora, known locally as the Iron Greenway, a popular route for those wishing to explore the path of this remarkable mineral railway.