The correct answer is: A. T/A-602
T/A-602 is a train authority to proceed document that is used in single line sections during train traffic control (TFC). It is issued by the train dispatcher to the driver of a train that is authorized to proceed in the opposite direction of normal traffic flow. The document includes the train’s number, route, and schedule, as well as the authority to proceed over the single line section.
The other options are incorrect because they are not train authority to proceed documents. TG-602 is a train order, TH-602 is a train schedule, and TB-602 is a train bulletin.
Train orders are instructions issued by the train dispatcher to the crew of a train. They are used to control the movement of trains and to ensure safety. Train schedules are documents that list the times that trains are scheduled to depart and arrive at stations. Train bulletins are documents that provide information about changes to train schedules or other operational matters.