The Track Flick alert is designed to fire when a track circuit transitions from occupied to unoccupied under a given time. The amount of time provided in the alert should be any value lower than the fastest valid occupation time for the track circuit.
The alert should correctly capture the following conditions;
- Track circuit flicking during passage of a train
- Track circuit flicking with no passage of train
Real Example
(AH track circuit transitioned from Dn to Up in 460 milliseconds)
 | AH TPR | Up | 13:29:25.380 | Note: Replay confirms there is no occupation of TRs in either direction Derived Assumption: No train was in section |
 | AH TPR | Dn | 13:29:27.420 | |
| AH TPR | Up | 13:29:27.880 | Note: Replay confirms there is no occupation of TRs in either direction Derived Assumption: No train was in section |
Inputs
| Track Circuit TPR | The track circuit input channel to monitor |
|---|---|
| Minimum Occupation Time (s) | The minimum valid occupation time in seconds for the track circuit |
Logic
When the TPR transition time from occupied (Dn) to unoccupied (Up) is less than the minimum occupation time, the alert will fire.