ST185s

The ST185s is a model of diesel-electric locomotive produced by the British Rail Engineering Limited (BREL) for British Rail. Introduced in the late 1970s, it was designed as part of the Class 59 series, though it is often referred to separately due to its unique specifications. The ST185s was primarily intended for heavy freight duties, particularly hauling coal and other bulk goods across the extensive British railway network.

The locomotive is powered by a 3,300 horsepower (2,460 kW) Paxman Valenta 16-cylinder diesel engine, which drives a DC electric transmission system. This setup provides strong acceleration and the ability to handle heavy loads on steep gradients. The ST185s features a distinctive, boxy design with a high roof, which houses the engine and auxiliary systems. It was built to meet the demands of British Rail’s modern freight operations, offering reliability and efficiency for long-distance hauling.

The ST185s was part of a small batch of locomotives, with only a handful produced. Its design was influenced by earlier British freight locomotives, such as the Class 56, but it incorporated advancements in diesel technology and mechanical reliability. The ST185s was later reclassified as part of the Class 59 series due to its operational similarities, though it retained some unique characteristics.

Over time, the ST185s saw limited use, primarily in freight services, before being gradually withdrawn from service in the late 1990s and early 2000s. Some examples were preserved by heritage railways, where they continue to operate on preserved lines, offering enthusiasts a glimpse into British freight locomotive history. Today, the ST185s is remembered as a robust but niche locomotive, representing an era of British diesel freight engineering.