"She said the thing blows if the no-tampering signal fails."

Otherwise, again, the signal would fail to return to danger.

If the wire snaps the signal automatically fails safe and returns to danger.

This signal may be used when a main signal fails.

One white light on Hp signal: This signal has failed or is otherwise out of use.

She swore again, but managed to fix the coordinates precisely before the signal failed.

When a signal fails to clear, depending on the area, there are three different ways to rectify the situation.

But because the signal failed, the local train left Shigaraki 10 minutes late and the special train did not wait at the siding.

An automated signal that should have warned of the error apparently failed to sound as well.

A few metres ahead of Dhanushkodi, the signal failed.