Dealing with a track section that shows a false "occupied" status

Occassionally, the interlocking plant shows that a track section is occupied when in fact it isn't. In such a case, the first job of the operator in the Altstetten control center is to determine where the trains are. This is more difficult than in the days where every station was manned, because the operator usually cannot see the trains.

The Altstetten operator must call the driver of the last train over the track section and verify that part of the train was not somehow left behind.

Until the false occupied indication can be corrected, a paper-based system involving checklists and forms is used so that trains continue to get authorization to enter the track section only when it is safe to do so.

See also assuring safety.