What should be done if a portion of a train is left on the main track temporarily?

Setting sufficient hand brakes and providing protection is crucial when a portion of a train is left temporarily on the main track. This action ensures the safety of both the train and the surrounding environment. Hand brakes are essential for securing the train and preventing it from rolling, which could pose a significant hazard, especially on inclined tracks or if there are changes in weather conditions.

In addition to setting hand brakes, providing protection typically involves following specific procedures such as placing warning signals at a safe distance from the train. This alerts other trains or crews of the situation, allowing them to take necessary precautions, thus maintaining the safe operation of rail traffic in that area.

While leaving the area immediately might seem like a quick solution, it fails to address the immediate safety risks and could lead to accidents. Using only visual signals for securing a detached portion does not provide adequate safety measures, as it lacks the physical security that hand brakes offer. Notifying adjacent crews verbally is important but should not be the sole action taken since it doesn't secure the train itself or provide immediate protection for passing trains. Hence, setting hand brakes and providing protection is the preferred course of action in this scenario.