Under what circumstances can engineering service employees line main track switches?

Engineering service employees are permitted to line main track switches when authorized by an employee in charge. This ensures that safety protocols and operational guidelines are adhered to, providing a structured environment for making decisions about track usage. The authorization process involves communication and oversight from a designated authority, which helps prevent potential accidents or miscommunication that could arise from uncoordinated actions on the main track. By requiring an official authorization, the system maintains a hierarchy and accountability, which is crucial in train dispatching and railroad operations.