What signal indicates that a train may approach facing points of a spring switch in non-signaled territory?

In non-signaled territory, the appropriate indication for a train approaching facing points of a spring switch is a proper lining signal. This signal conveys critical information to the train crew, ensuring that the switch is aligned correctly for the train's safe passage. The proper lining signal typically confirms that the route ahead, including the switch placement, is set up to avoid danger, especially given the potential complexities of spring switches.

A proper lining signal provides essential reassurance to the crew, allowing for safe operations without reliance on conventional signaling apparatus. It helps maintain safety protocols by ensuring that the train approaches the switch with the necessary awareness of its alignment and readiness.

Other choices such as a stop signal would indicate the need to halt, which does not convey the necessary information about the switch alignment. A switch indicator might inform crew members about the current position of the switch but does not communicate the safety of the approach. Similarly, while a distant signal may display clear, its primary function is not specific to indicating the configuration of switches ahead, and thus it may not provide the necessary assurance regarding the spring switch configuration.