Which aspect of signal on Automatic section while showing “A” & “AG” both light-up?

Gate closed and point is set for main line
Gate opened and point is set for main line
Gate opened and point is not set for main line
Defective signal

The correct answer is: Gate closed and point is set for main line.

When a signal on an Automatic section shows “A” and “AG” both light-up, it means that the gate is closed and the point is set for the main line. This means that the train can proceed through the signal without stopping.

The other options are incorrect because:

  • Option B is incorrect because the gate is closed, not opened.
  • Option C is incorrect because the point is set for the main line, not not set for the main line.
  • Option D is incorrect because the signal is not defective.

I hope this helps! Let me know if you have any other questions.