What is the term for a block where no train is allowed to enter if it is occupied by another train or equipment?

The term for a block where no train is permitted to enter if it is already occupied by another train or equipment is known as an "Absolute Block." This concept is crucial for maintaining safety and preventing collisions on the railway. An Absolute Block ensures that only one train occupies a particular section of track at a time. This regulation helps to manage train movements effectively, ensuring that when one train is present in a block, no other train can enter it until the first train has cleared the area.

In contrast, while terms like "Controlled Block" and simply "Block" may refer to different methods of managing train movements, they do not specifically imply the strict prohibition of entry for occupied sections like an Absolute Block does. "Deadhead Train" refers to a train that is running without a load or operational purpose, rather than being related to the occupancy rules of tracks.

Understanding the concept of Absolute Blocks is essential for ensuring safe operations within rail systems and minimizing the risks of accidents related to train movements.