Railway signal box

The image is a black and white photograph of a railway signal box, which is a building used to control railway traffic. 

Signal boxes were an integral part of the "block" system, introduced between the 1860s and 1880s, to maintain a safe distance between trains. 

The box in the image has a brick lower level and a timber upper cabin. 

This specific type of structure is a common design used on British railways. 

Many historic signal boxes remain in situ or are moved to heritage railways after retirement.