When is an interlocking appliance considered BLOCKED?

An interlocking appliance is considered BLOCKED when it is either disabled electrically or when an approved device is applied. Each of these scenarios indicates that the appliance cannot operate as intended, which is a critical aspect of maintaining the safety and functionality of rail operations.

When an interlocking appliance is disabled electrically, it means that it is not receiving the power necessary to function. This state ensures that the appliance cannot inadvertently allow conflicting movements of trains, thus enhancing safety by preventing potential accidents.

Applying an approved device to the interlocking appliance adds an additional layer of security. This device functions to physically prevent any movement through the interlocking, thereby ensuring that trains cannot pass through the section controlled by that appliance under unsafe conditions.

Both situations—being disabled electrically and having an approved device applied—serve to remove the influence of the interlocking appliance from the train control system, effectively BLOCKING its operations and maintaining safe conditions on the rail line.