On a ten-car train set up for two-conductor operation, how many drum switches must be set in the OFF position?

In a two-conductor operation setup for a ten-car train, it is essential to understand the function of drum switches and their configuration within the train’s electrical system. Typically, drum switches control the electrical circuits associated with the train's power and communication systems.

In a standard configuration, one drum switch is required for each end of the train, as well as additional switches based on the number of cars. For a ten-car configuration set up for two-conductor operation, there would typically be one drum switch per car to allow for proper isolation of cars within the train set.

As the scenario involves two-conductor operation, the need arises to ensure specific circuits must be disabled for safety and operational efficiency. Therefore, it is common practice to have a specified number of drum switches set to the OFF position to maintain safe operations and fulfill the requirements for isolating certain sections of the train from electrical power.

Thus, the fact that four drum switches must be set to the OFF position is based on the need to safely manage various electrical loads across the ten-car configuration, ensuring that the system operates correctly while following the prescribed safety measures in train operations. This focus on proper switch management underscores the operational protocols necessary for maintaining train safety and performance during operation.