What system initiates a penalty brake application if the engineer fails to reduce speed according to cab signal indications?

The Automatic Train Control (ATC) system is designed to enhance safety by ensuring that trains operate within set speed limits and respond appropriately to signal indications. If the engineer does not reduce the train's speed in accordance with the cab signal indications, the ATC system will automatically initiate a penalty brake application. This action serves as a protective measure to prevent potential accidents or unsafe conditions on the tracks by reducing train speed if the engineer fails to follow the operational guidelines.

In this context, the other options do not fulfill the same function. The Control Console is a central interface for the engineer but does not autonomously apply brakes. The Locomotive Speed Limiter is designed to restrict the maximum speed but does not directly respond to cab signal breaches by initiating a penalty application. Work Limits refer to specific areas where trains must adhere to certain operational rules and do not apply the penalty brakes automatically based on cab signals. Thus, the ATC system is the essential component that takes action in the event of non-compliance with cab signals.