both-way signalling
51Professional Mobile Radio — (also known as Private Mobile Radio (PMR) in the UK and Land Mobile Radio (LMR) in North America) are field radio communications systems which use portable, mobile, base station, and dispatch console radios and are sometimes based on such… …
52Channel Tunnel — Map of the Channel Tunnel Overview Location English Channel (Strait of Dover) Coordinates Folkestone …
53Handicap principle — The tail of peacocks, the classic example of a handicapped signal of male quality The handicap principle is a hypothesis originally proposed in 1975 by biologist Amotz Zahavi[1][2 …
54Dual gauge — Track gauge by size Broad gauge Sta …
55Communications-based train control — CBTC deployment in Metro de Madrid, Spain …
56Delhi Metro — दिल्ली मेट्रो Info Locale NCR, India (Delhi, Gurgaon, Noida) …
57Nervous system — Nerve redirects here. For other uses, see Nerve (disambiguation). This article is about the nervous system. For parts of the nervous system commonly called nerves, see Peripheral nerve. Nervous system The Human N …
58Phreaking — is a slang term coined to describe the activity of a subculture of people who study, experiment with, or explore telecommunication systems, like equipment and systems connected to public telephone networks. The term phreak is a portmanteau of the …
59Train station — Rail transport Operations Track Maintenance High speed Gauge Stations …
60Level crossing — This article is about at grade intersections between railway and road. For where two rail lines cross, see level junction. For a type of nuclear receptor (RXR), see Retinoid X receptor. A level crossing at Chertsey, England, as the barriers rise …
