Metropolitan Transportation Authority (MTA) Assistant Conductor Practice Test

What does a Block Limit Signal indicate in the Manual Block System (MBS)?

1. A fixed signal indicating the limit of a block

2. A signal that permits a train to proceed at full speed

3. A warning signal for upcoming switches

4. A signal for determining train positions

The correct answer is: A fixed signal indicating the limit of a block

A Block Limit Signal in the Manual Block System (MBS) specifically indicates the limit of a block. This type of signal is crucial for maintaining safe separation between trains and ensuring that they do not enter a block that is already occupied by another train. The block is essentially a designated section of track where only one train is allowed to occupy at a time, and the Block Limit Signal defines when this section begins and ends. When a train approaches a Block Limit Signal, it can determine whether the next block is clear or not. If the signal indicates that the block is occupied, the train must stop. Conversely, if the signal shows that it's clear, the train can proceed safely into the next section of track. This functionality is fundamental to preventing collisions and ensuring orderly movement on the railway, highlighting the importance of the Block Limit Signal in the overall operation of the Manual Block System.