signalfel

Etymology
From.

Noun

 * 1)  collective term for error signals from the safety system which assess, for yet unknown reason, that the route cannot be operated safely (e.g. a broken light bulb, blocked switch, faulty communication antenna, unknown position of a train, or an open railway barrier)
 * 2) * 2020 October 26, headline on svt.se:
 * "sv"

- Signalfel orsakar stora förseningar i tunnelbanan

Usage notes
Despite what the name might suggest; the word does not refer to a faulty signal, but instead to the signal that indicating that something is wrong.