What is primarily checked if an escalator continues running despite a reset?

When an escalator continues running after a reset, the most relevant component to check is the start switch. This switch is responsible for initiating the operation of the escalator. If the start switch is faulty or stuck in the 'on' position, it could cause the escalator to ignore a reset command and continue running.

The functionality of the start switch is crucial because it directly controls the operational state of the escalator. If it does not disengage or isn't responding correctly, the escalator can exhibit persistent operation even after a reset attempt, leading to a potential safety concern.

In addition, while the control panel, power supply, and handrail system are important components of the escalator's overall operation, they have different roles. The control panel manages various operational commands, the power supply delivers the necessary energy to the system, and the handrail system typically aids in user safety and comfort. In this scenario, the start switch's direct link to operational initiation makes it the primary suspect when an escalator continues running unexpectedly.