- Not restricted or confined.
- 1950 March, H. A. Vallance, “On Foot Across the Forth Bridge”, in Railway Magazine, page 147:
- The extreme depth of these channels, and the insistence of the Board of Trade on a headway of 150 ft. for the unrestricted passage of large ships, necessitated a high bridge with two main spans, and a central pier on Inchgarvie.
- 1962 June, David Walters, “The new station and layout at Coventry”, in Modern Railways, page 407:
- The new fast lines are laid out for unrestricted speed through the station, as after electrification certain expresses may run non-stop between Euston and Birmingham.
- Having no security classification.