What is the key function of a block system?

The key function of a block system is to authorize train movements. This system is designed to ensure safe and efficient train operations by dividing the railway into sections or 'blocks.' Each block can only be occupied by one train at a time, which prevents collisions and enables system operators to regulate train movements effectively.

When a train is granted permission to enter a block, this authorization indicates that the block is clear of other trains, allowing for safe passage. This is crucial for operational safety, helping to prevent accidents. The block system is integral to signaling and communication between train crews and dispatchers, ensuring that all movements are coordinated and safe.

While controlling train speeds and limiting the number of trains are important aspects of train operations, they are secondary to the primary function of ensuring that trains have the appropriate authorization to enter each block. Similarly, while maintenance schedules are vital for the overall operation of the railway, they are not the main concern of the block system itself.