Railway lineside cabins known as Black Boy Stables

This group of four ancillary buildings, known as Black Boy Stables, dates from the early to mid-19th century and were originally constructed for railway staff working on the Stockton & Darlington Railway, with one building added between 1897 and 1915. They are built of roughly coursed sandstone rubble with restored Welsh slate roofs.

The group consists of four single-celled buildings. The largest sits centrally and is semi-detached to a building (Building 2) to the northwest, which in turn has a further building (Building 3) attached to its rear (northeast). A detached building, Castle Cabin, is located just under 2 metres to the southeast of the central building. The Black Boy branch line ran on the northeastern side of the complex, the Surtees Railway branch line on the southwestern side, and the original main line of the Stockton & Darlington Railway to the south.

The central building is single-storey with an attic, comprising three bays with a central door flanked by window openings facing southwest. It has coped gables, an attic opening in the southeast gable, and a ground-floor window in the northwest gable, which is partially covered by the attached Building 2. The rear wall, facing the Black Boy branch line, is blind. Building 2 has a single-pitched roof that slopes from its tall, front (southwest) wall, which contains the building's single door and window. Building 3, a later addition, is attached to the rear (northeast) of Building 2 and built on slightly higher ground. It features a double-pitched roof with coped gables and a double-width doorway filling the northeast side. Castle Cabin has a shallow, mono-pitched roof sloping from its southeast side, where the doorway is located and which overlooked the original main line of the Stockton & Darlington Railway where it joined the two branch lines. The two side walls each have a single window, with the southwest wall being curved, cutting back the southern corner of the building.

The interiors of the buildings feature unplastered walls and block-paved floors.