Negative AC energy for track indicator light?

• A. Te
• B. Tb
• C. Toh
• D. TeCx

Answer: (D)

Understanding how track indicator lights are powered and labeled helps decode these options. TeCx designates negative alternating current used specifically for a track indicator lamp. The base Te signals track energy, while the C (common) shows the return path, indicating the polarity is negative with respect to the positive supply. The x marks the particular indicator circuit being referenced. In practice, using this label makes clear that the indicator is driven by the negative AC energy path of the track circuit, which is important for correct operation and wiring.

The other labels would refer to different sources or uses (for example, a general track energy without specifying the negative return, or a different source type entirely), so they don’t pinpoint the negative AC energy path for the indicator like TeCx does.