How long should a train wait before entering ABS territory without permission?

A train must wait for 5 minutes before entering ABS (Automatic Block Signal) territory without permission. This waiting period is a safety protocol designed to ensure that the area is clear and that the train does not inadvertently interfere with other operations or trains that may be in that territory without proper authorization. The 5-minute interval allows for any potential updates, clearance, or communication issues to be resolved, increasing the overall safety and efficiency of train movements in ABS territory. By adhering to this protocol, dispatchers can minimize the risk of accidents and maintain orderly train control, which is essential in busy rail operations. The other time intervals do not provide an adequate level of safety assurance or align with established operational guidelines.