Metropolitan Transportation Authority (MTA) Assistant Conductor Practice Test

The Approach Restricting signal is the correct indication for restrictions on approach in train operations. This signal is specifically designed to inform train operators that they are approaching a signal that may require them to prepare to stop or reduce speed. When a train encounters this signal, it indicates that there will be a change in the conditions ahead, such as a potential stop signal or a restriction due to track conditions.

This signal can be crucial for ensuring the safety and proper operation of trains, as it provides advance warning to the engineer, allowing them to take appropriate action to ensure the train's safe operation as it approaches a potentially restrictive situation.

In contrast, other signs such as a Diverting Approach sign focus on guiding trains towards diverging tracks rather than indicating restrictions, while a Speed Limit sign outlines the maximum safe speed for a given section of track without necessarily signaling an impending restriction. An End of Block sign marks the conclusion of a signal block and does not relate directly to restrictions on approach. Thus, the specific function of the Approach Restricting signal is particularly important in the context of railway safety and operational protocols.