|For general information on use cases see UC:Use cases|
Use case / Anwendungsfall
Description / Beschreibung
Possession is a takeover of responsibility for a part of railway network from the “train operator” to the PICOP (Person In Charge Of Possession). The objective of a possession is to ensure safe construction/maintenance works on the railway infrastructure. The safety is ensured by a set of safety measures:
- Temporal speed restrictions around the construction work (including neighbour tracks if needed)
- Closed tracks for most of the trains except the specific once.
- Specific position of the switches (similar to flank protection)
Possession management is safety relevant as any failure could result e. g. in a collision of passenger train with a construction train with > 1000 involved people. Possession undergoes a specific life cycle (here the default “path”):
- It is planned by the maintenance system, defining elements to be worked on and additional definitions (e. g. used machines) which could influence the required safety measures.
- The safety measures are planned by a signalling specialist.
- Timetable planning department defines time intervals for activation, as well as rules for disturbed case (e. g. let Train 1002 pass if delayed less than 5 minutes).
- Train operator modifies planned time intervals according to the expected traffic situation, e. g. by postponing start of possession.
- When the PICOP and his team arrive at possession area
- He safely identifies his location, to prevent activation of wrong possession
- Requests the activation of Possession
- The train operator verifies,
- That timetable requirements for disturbed case are implemented (train 1002 has passed)
- No unexpected trains are inside of the possession area
- Train operator activates the speed restrictions defined in Possession.SafetyMeasures
- Train operator puts switches in positions defined in Possession.SafetyMeasures
- Train operator verifies all the safety requirements defined in Possession are fulfilled
- Train operator notifies the PICOP about the possession activation
- PICOP and his team start working
- After PICOP finished the work
- He ensures, that his team has left the possession area and it is ready for operations
- He requests the train operator to finish possession
- Train operator
- releases blocked switches
- removes temporal speed restrictions
- closes the possession
To make the life more complicated, the lifecycle of possessions can vary:
- possession can be stopped and reinstated later
- two possessions can be assigned to one PICOP
- one big possession could be split into two small once, without deactivation/reactivation phase
- PICOP could require to move possessed switches to check their proper function.