Why are interlocking schedules used?

In railway signalling, an interlocking is an arrangement of signal apparatus that prevents conflicting movements through an arrangement of tracks such as junctions or crossings. The signalling appliances and tracks are sometimes collectively referred to as an interlocking plant. An interlocking is designed so that it is impossible to display a signal to proceed unless the route to be used is proven safe.

What do you think about music? do you like words? do you like dancing? do you like that kind of music? how long have you listened to this type of music? btw im in the same spanish class ; )

Can you do it again i can't really read it