Metropolitan Transportation Authority (MTA) Assistant Conductor Practice Test

What is an absolute block?

1. A block where no train is allowed to occupy while another train is present

2. A length of track defined by block limit signals

3. A segment of track used solely for freight transport

4. A block controlled by manual signals

The correct answer is: A block where no train is allowed to occupy while another train is present

An absolute block is defined as a segment of track where only one train is allowed to occupy the block at any given time. This ensures that no two trains can be present in the same block, which is crucial for maintaining safety and preventing collisions. The concept of absolute blocks is important for safe train operations, as it establishes a clear and defined area that trains must clear before another can enter. When considering other options, a length of track defined by block limit signals relates more to the general signaling and control of train movements, which may not necessarily enforce the absolute occupancy rule. A segment of track used solely for freight transport does not define the functionality of the block in terms of occupancy. Lastly, a block controlled by manual signals speaks to the method of control but does not inherently imply the occupancy restrictions that an absolute block encompasses. Therefore, the definition surrounding the occupancy limitation is what makes the first choice the correct answer.