TripAdvisor, Inc. is an American travel website company providing reviews of travel-related content. It also includes interactive travel forums.TripAdvisor was an early adopter of user-generated content. The website services are free to users, who provide most of the content, and the website is supported by an advertising business model.
A coupling (or a coupler) is a mechanism for connecting rolling stock in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.
