Fellesmodussignalet

Fellesmodussignalet is a Norwegian railway signal used to indicate the location and direction of a train's departure and arrival. Developed in the early 20th century, it is a non-electronic, audible signal that uses a series of bells and blowers to communicate information to train dispatchers and other personnel.

The signal consists of a combination of three bells - two positioned above each other and one below - which ring in a specific sequence to convey the necessary information. The tone of the bells and the pattern in which they ring indicate whether the train is departing or arriving, its destination, and any relevant engineering information.

The first two bells above each other signal the location of the train's movement - one for departure and one for arrival - while the single bell below confirms the train's route and any special instructions, often light signals, that require attention. The frequency and duration of the bells are used to convey additional information, such as a change of destination or cautionary signals requiring response from the operating crew.

The use of fellesmodussignalet was widespread throughout the Norwegian rail network before the introduction of electronic communication systems and computer-controlled signaling. In more rural areas where resources were scarce, fellesmodussignalet remained the primary means of signal communication until as late as the 1980s.