The PZB (inductive train protection) is a system that forces trains to a standstill in case of driving too fast towards a stop. A running train is influenced by the interaction of magnets on the track and within the train.
The magnets in the train induce the frequency 500Hz, 1000Hz or 2000Hz each to the respective trackside magnets. The induction is a signal for the crossing of an active trackside magnet and leads to a velocity control depending on the section where the train is located. If the train driver has not seen a stop signal and does not deccelerate to a required velocity an emergency brake is triggered. Some parts of the PZB are disregarded within our case study as the fault mode and train changes.
Modeling with SAML:
For this case study, we modeled relevant components such as the trackside and train magnets, the driver, the train itself and the human-machine interface in SAML within templates. The train is represented by its current position, velocity and acceleration. A route with 1500m length is considered with a stop signal and arbitrary trackside magnets. For reasons of state space reduction this route is abstracted from 1m per simulation step to 2m per step. To model non-deterministic behavior of the train driver, in each step a choice is given how he will act in the next step. The templates are connected with each other via a PZB main component.
For the velocity control a velocity curve as a constraint is required. This curve is expressed by a component which takes a value depending on the time that has passed after starting the control. Therefore, all of the different cases have to be considered within transitions.