Metropolitan Transportation Authority (MTA) Assistant Conductor Practice Test

The correct response indicates that a train must not pass a Block Limit unless specifically authorized. This is important because Block Limits are established safety thresholds designed to prevent collisions and ensure safe train operations. They are designated areas where trains must stop or are prohibited from entering unless given explicit permission, usually through signals or verbal communication from dispatch or control centers.

Authorization ensures that train operators have appropriate clearance, which takes into account the entire operational environment, including the positions of other trains and any ongoing maintenance activities. Passing a Block Limit without such authorization compromises safety and can lead to serious accidents.

In contrast, the other choices do not encapsulate the safety protocols regarding Block Limits correctly. For example, the notion that trains should not pass Block Limits only during peak hours or only in emergencies fails to recognize the consistent requirement for authorization regardless of the time or operational situation.