21. TI21 type track circuits ( now known as " EBI" 22. These track circuits are limited in length to about 300m. 23. She competed on the 2011 IAAF Diamond League track circuit and established herself further. 24. This upgrade will install signals, track circuits and automatic speed control ( ASC ). 25. Signalling and safety systems on both sections included track circuit and absolute block signalling. 26. If part of the train remains in the section, the track circuit detects that part. 27. Another factor in the accident was the failure of a track circuit in the area. 28. McGhee was a regular feature on the international professional track circuit in the late 1990s. 29. Automatic Route Setting, Automatic signal and track circuit failures. 30. The whole railway was resignalled by 2006 with track circuits replacing the treadle-operated signalling system.
