Air traffic controllers do not keep records of the traffic they handle. An integral part of the train dispatcher’s minute to minute handling of traffic is record keeping. Train dispatchers maintain a record called a trainsheet which shows engine numbers, conductor and engineer names, times on and off duty, number of cars in each train and the tonnage, the times trains arrive, leave and pass stations, the weather at 6 hour intervals and a description of train delays and any unusual occurrences. The trainsheet is the legal record of the company’s operation for that dispatcher’s territory and may even be subpoenaed as evidence in case of lawsuit or other legal action. All telephone and radio circuits of train dispatchers, like those of air traffic controllers, are recorded. In addition, all instructions issued by the dispatcher are written as they are issued by voice, then underscored as they are repeated both to insure accuracy and to provide a paper trail for accident investigation, should one occur.