Timetables enable safe and coordinated movement
A timetable is a published schedule of the movement of trains which lists the trains, locations along the railroad line, and times at which certain events, such as arrivals and departures at a station or siding, are expected to take place.
Initially timetables were one-sheet broadsides, listing arrival and departure times for station stops, posted in the railroad stations and other public buildings. These broadsides often measured 10 by 15 inches or larger, and were likely inspired by the stagecoach and steamboat schedules of the time. Some early timetables were designed for employees as well, listing the principal operating rules on the reverse side.
On May 23, 1830 the first railroad timetable, for the Baltimore and Ohio Railroad, was published in the Baltimore American newspaper. As railroad companies grew following the Civil War, broadsides were replaced by separate published public and operating (employee) timetables.
During the early years most trains were operated on a single track, with sidings provided at intervals to allow trains to pass each other. Timetable operation was developed in order to avoid collisions between trains and to move trains efficiently over the railroad lines. Steam locomotives were capable of moving trains faster than they could be stopped within sighting distance, thus trains could not be operated based on sight alone. Timetable operation is the simplest form of train operation and was the normal mode of operation on American railroads in the early years.
Using a timetable system, trains can only operate in pre-arranged time periods, during which they have 'possession' of the track and no other trains can operate. When trains are operating in opposing directions on a single-track railroad, meets are scheduled, where each train must wait for the other at a siding where they can pass. Neither train is permitted to move until the other has arrived. As timetables evolved the classification of each train was typically also included, indicating which train was more important and would get priority in train movement, first class passenger trains had priority over second class trains, etc. When operating using a timetable, everything is scheduled in advance and every train crew knows the timetable, and on many railroads keeps a copy with them.
The Virginia & Truckee Railroad line between Carson and Virginia was a single track line in 1870. In the Virginia and Truckee Railroad Time Table No. 1, Train Nos. 1 and 2 are scheduled to meet and pass each other at Mound House at 7:00 a.m. The first train to arrive will wait at the siding until the second arrives. Once both trains have arrived they can use the siding to pass, then each train can proceed to the next station listed on the schedule. Train Nos. 2 and 3 are scheduled to meet at Carson at 8:00 a.m., Train No. 3 will wait at Carson until Train No. 2 arrives. At the same time Train Nos. 1 and 4 are scheduled to meet and pass at Gold Hill, the first to arrive will wait at the siding until the second arrives, etc.
The timetable system has disadvantages. The first is that there is no positive confirmation that the track ahead is clear; only that it should be clear. This system does not allow for breakdowns and other such problems. The timetable is set up in such a way that there should be sufficient time between trains for the crew of a broken-down or delayed train to walk back up the line far enough to set up warning flags, flares and other signals to alert a train crew to a blocked track ahead.
The second problem is the timetable system's inflexibility, trains cannot be added, delayed or rescheduled, making it inefficient as traffic increased on a railroad line. To give a little flexibility, the timetable must give each train a broad swath of time to allow for some delay. Thus, the line is possessed by the train for a much longer period than is really necessary. If a train was delayed, no other train could move until the delayed train eventually showed up at the meeting point, even if the opposing train were hours late.
Telegraph Enables Adjustments When Needed
With the introduction of the telegraph, a more sophisticated system became possible because the telegraph provided a means to transmit messages faster than the trains moved. The telegraph could be used to communicate the arrival and departure of trains at stations along railroad lines. Timetables continued to provide the schedule and general priority of train movement, however adjustments could be made and communicated using a telegraph and Train Orders which override the timetable, allowing the cancellation, rescheduling and addition of trains, and almost anything else.
Today timetable and train order operation has been replaced by radio dispatching on many light-traffic lines and electronic signals on higher-traffic lines. Train movements are still authorized in the name of the superintendent of each railroad division, by the current employee timetable, and by orders issued by the train dispatcher. Rules governing timetable and train order operation include superiority of trains or which train will take the siding at a meeting point, time spacing or the time a train following another must wait before leaving a meeting point, and methods of signaling.
Text by Richard Boehle.
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