In what situation can a train proceed without on-ground warning when crossing gates are down?

A train can proceed without on-ground warning when crossing gates are down if a qualified employee is available at the crossing. This situation allows for the presence of a person who can provide the necessary assurance that it is safe for the train to proceed. The qualified employee's role is crucial as they are trained to manage the safety protocols around the crossing and ensure that no vehicles or pedestrians are in the way of the train.

While other factors, such as flashing lights or observed traffic conditions, may indicate something about the safety of the crossing, they do not offer the same level of assurance or authority to proceed as a qualified employee does. Additionally, the authorization of an Engineer or the flashing lights alone do not constitute the proper safety measures set forth by the regulations for such scenarios. The presence of a qualified employee provides a layer of oversight that maintains safety and compliance with operational rules.