When is a PPOS allowed on a track?

A PPOS, or Positive Protection Overlay System, is permitted on a track specifically when working limits have been established and no movements have been permitted. This is critical for the safety of roadway workers, as it ensures that the area they are working in is secure from any rail movements. Establishing working limits means that the necessary measures and communications have been made to ensure that train operations are stopped within those limits, thereby creating a safe environment for workers.

In contrast, allowing a PPOS at other times, such as during general operations, routines, or emergencies without the proper safety protocols in place, could lead to dangerous situations, including accidents or injuries. Only under the defined conditions of established working limits can the PPOS effectively serve its purpose of protecting workers on the track. This reinforces the importance of following protocols and prioritizing safety in all aspects of rail operations.