How do electrical and communications signals pass from one car to another?

Electrical and communications signals pass from one car to another primarily through the electrical portions in the coupler. The coupler is a mechanical device that connects individual railcars and also facilitates the transfer of electrical signals. These signals are essential for communication between cars, enabling functionalities such as signaling system integration, control operations, and safety mechanisms throughout the train.

The electrical design of the coupler includes connectors that ensure a secure and reliable transfer of power and data, allowing the onboard systems of each car to work in unison. This connectivity is critical for maintaining operational efficiency and coordination across the train's systems, such as activating brakes, controlling lights, and managing other communication systems when the train is in motion.

Other methods like visual indicators or onboard computers serve different purposes and do not facilitate direct signal transfer between cars. While wireless technology has its applications, in the context of the direct connection between train cars, it does not replace the established electrical connections provided by the coupler system.