This series contains files of the Railway Inspectorate concerning safety provisions for railways. The files cover various aspects of railway safety, such as track inspection, accident investigation, staff health and safety, and operating system inspection. Most files relate to train accidents and new works. Many files concern safety modifications to level crossings.

Files are usually listed in groups under headings of the main railway regions (Southern, Western, Eastern, North Eastern, Scottish, London Midland, and London Transport). There are also files concerning the triple collision at Harrow in 1952 and the Hixon level crossing accident of 1968.