which were not in the timetable, and scheduled trains moving contrary to their normal authorities. Timetable and train order operation supplanted earlier forms of timetable only and line-of-sight running. The ability for a single dispatcher to issue train orders was enabled by the invention of the electric telegraph in the 1840s. The earliest recorded usage of the telegraph to convey train orders in the US came in 1851 on the Erie Railroad and by the time of the American Civil War, nearly every railroad had adopted the system. Gradually the telegraph was supplanted by the telephone as the preferred method of communication. By the 1970s this function was carried out primarily by two-way radio. With the advent of radio communications, timetable and train order operation began to fall out of favor as direct traffic control and centralized traffic control (CTC) became more common on major carriers. CTC enabled dispatchers to set up meets remotely and allowed trains to proceed entirely on signal indication. Where signals were not present, DTC and the related track warrant control allowed dispatchers to directly inform trains what they were to do instead of needing to work through intermediaries or have the train crews figure things out for themselves. Train order The train order provides the means to deal with changes in operating conditions as they arise. Orders modify the established timetable. Among the functions a train order can perform are: Creating a train not provided for by the timetable (an "extra") Annulling a train provided by the timetable Creating sections of a schedule (in essence "cloning" a train's schedule and class when, for example, too much traffic exists to be handled by a single train) Setting meeting points between extras since they have no timetable schedule Altering timetable meeting points (for example when one train is late and adhering to the timetable meeting point would cause delays for other trains) Altering the schedule of a train to allow other trains to run with respect to the altered schedule rather than that given in the timetable Giving a train rights over another train that ordinarily has timetable superiority Conveying warnings about temporary conditions such as temporary speed limits, track conditions or hazards which might affect the safety of trains or train crews Train-order station A train-order station is a control point at which trains can be stopped and controlled through the use of train orders. A