Define 'block system' in railway terminology.

The 'block system' in railway terminology refers to a method for controlling train movements to prevent collisions. This system divides the railway network into sections or blocks, which can only be occupied by one train at a time. By using signals and various forms of communication, the block system ensures that trains can only enter a block that is confirmed to be clear and not occupied by another train. This effectively enhances safety by minimizing the risk of accidents and collisions on the tracks.

It is crucial for the efficient operation of rail systems, especially in busy networks where multiple trains may be operating simultaneously. The block system can involve both manual and automated control methods and is foundational for modern railway signaling practices.