both-way signalling
21Northern Counties Committee — The Northern Counties Committee (NCC) was a railway that served the north east of Ireland. It was built to Irish gauge (1,600 mm (5 ft 3 in)) but later acquired a number of 914 mm (3 ft)  narrow gauge… …
22Railroad switch — For other uses, see Switch (disambiguation). A right hand railroad switch with point indicator pointing to right …
23New York City Subway — Top: A number 4 train made up of R142 …
24Chiltern Main Line — Chiltern Railways Clubman at West Ruislip Overview Type Commuter rail, Heavy rail S …
25Great Central Railway (preserved) — Great Central Railway Great Central Railway D123 Kinchley Lane Locale Loughborough, Leicestershire, England Terminus Leices …
26Adenosine triphosphate — For the Japanese rock band, see Adenosine Tri Phosphate (band). Adenosine triphosphate …
27High Speed 1 — approaching the Medway Viaducts …
28International Regulations for Preventing Collisions at Sea — The International Regulations for Preventing Collisions at Sea 1972 (COLREGS) are published by the International Maritime Organization (IMO), and set out, inter alia, the rules of the road or navigation rules to be followed by ships and other… …
29GPO telephones — The United Kingdom s General Post Office (GPO) had a number of telephones that were provided by them for connection to their exchanges. Until 1982 the GPO had a monopoly on the provision of all telephones within the UK and so the range was… …
30Invention of radio — Great Radio Controversy redirects here. For the album by the band Tesla, see The Great Radio Controversy. Contents 1 Physics of wireless signalling 2 Theory of electromagnetism …
