Overground

Overground is a term used in transportation and urban planning to describe rail or tram lines that operate on the surface or at elevated levels, rather than in underground tunnels. It is commonly used to distinguish above-ground transit services from underground metro systems. The designation can apply to branding, service design, and route classification in various cities around the world, reflecting differences in construction, operations, and integration with other public transport.

The most widely known use of the term is London Overground, a network of suburban rail services in London and surrounding areas. Established in 2007 by Transport for London, London Overground brought together several previously separate National Rail routes under a single brand to improve reliability, connectivity, and accessibility. The network expanded through the revival and integration of lines such as the East London Line and other routes formerly operated separately, creating a coordinated system that interfaces with the London Underground and other rail services. The Overground is marketed with its distinct branding, including an orange color on maps and signage, and it accepts Oyster cards and contactless payments. It uses modern rolling stock and serves hundreds of stations, playing a key role in providing cross-city connections that complement the underground network.

Beyond London, the term overground may be applied descriptively to other surface or elevated rail operations in different cities, emphasizing above-ground mobility as contrasted with subterranean transit.