LZB to PZB transition

[Valdez]

I had an interesting experience on my last drive, GM60205 on Lehrte-Harburg driving the DB BR151 so no AFB to worry about.

I was driving under LZB at 100km/h, braking down to 60 as indicated. The LZB Ende light illuminated and I acknowledged with PZB Frei. All was well, until out of nowhere I had a PZB emergency stop.

I think what happened is when LZB ended I was still at 58km/h, below the signalled speed, but above the PZB 55 limit which had been running “in the background”, so although I complying with the line speed, PZB wasn’t happy and when LZB ended it immediately commanded a stop.

So my question is when LZB Ende is indicated, must you drive as if PZB was enabled from that point onwards? How would real drivers handle this situation?

[snookerfan]

So my question is when LZB Ende is indicated, must you drive as if PZB was enabled from that point onwards? How would real drivers handle this situation?

Yes. At least you should know which speed limit of the PZB surveillance LZB releases you into.
(A common trap is if you have a scheduled stop within the LZB Ende (e.g. in the Ausgsburg-Donauwörth timetable) you should be aware that LZB releases you to the restrictive mode of PZB.)

How would real drivers handle this situation?

He would brake down to at least 50.

[Marko Ramius]

see Zusi Documentation chapter 2.12.2.4.10 "LZB-end process" for details and how to handle

Particularly in the case of the PZB90, the driver needs to be aware during the LZB-end process that the Indusi system also receives and processes all speed controls during LZB operation, but does not display any of the information or activate enforced braking. The Indusi system thus comes out of background mode and becomes momentarily active at LZB end. If, therefore, a 1000 Hz speed control transmission was received, for example, the corresponding braking curve will immediately be activated, possibly even in restrictive mode after a stop, and will initiate an Indusi-enforced braking at LZB end. When the LZB-end process begins, the driver must therefore be able to identify from the trip profile what the status of the Indusi is when it becomes active, and drive at an appropriately low speed

You could call this PZB-behaviour "covert surveillance" because in the very moment the LZB ends the PZB gets active, and that in the state that was potentially triggered by influence during LZB-end process. This is exactly how it works in reality on german railroads.

And as far as I could read in the german section of this forum You are not the first driver having an unplanned stop because of this reason and I am pretty sure You won't be the last ...