STRATEGY AND TACTICS
Train dispatching is a science of strategy and tactics. The ultimate goal of the workday of a train dispatcher is the safe and economical operation of each dispatcher’s assigned territory. Promotion of the safe and economical operation of the railroads is even listed in the bylaws of the American Train Dispatchers Association, the union in which most U.S. train dispatchers are members, as one of the purposes of that organization. Train dispatchers are assigned a specific geographic territory, which is usually several hundred miles. The territory may be much shorter in areas of high traffic density or much longer in very light traffic areas. Typically, at the beginning of each shift while the planning of the previous shift is still effective, a dispatcher will formulate a basic plan for the operation of the traffic currently on the territory and that is expected. The operating plan must consider traffic expected and be effective for, depending on territory and traffic density, a period of several hours. Passenger trains must be considered first. The location at which opposing passenger trains will meet must be clear at the time that they will pass; there must be no freight trains or track maintenance work at those locations at those times. Important freight trains are considered next. Trains carrying mail or merchandise are next in importance to passenger trains and the locations at which these trains will meet passenger trains and each other as well as the locations at which passenger trains will pass the slower merchandise and mail trains must also be clear at the times that these trains will pass. Mandatory, major and deferrable track and signal maintenance must be considered in the plan. Repair of a defective rail can take 2 hours that is not interruptible once work has commenced. Replacement of a street crossing or section of track can take 8 hours or more. Preventive maintenance and some non-critical repairs can be deferred or at least flexibly scheduled during the day if traffic is heavy but serious defects must be repaired immediately and program maintenance involving large crews and expensive equipment must be carried out on schedule. Dispatchers must also be careful to avoid deferring maintenance or minor repairs until they become major defects and must be careful to ensure that maintenance workers remain as productive as possible.