20251: Which option is available in FBS to model trains with a very small train following distance (e.g. 120sec)? Are there possibilities to use "Moving Block"?

In fact, "moving block" is not possible in FBS without further effort, because then the driving dynamics of one (following) train would depend on the driving dynamics of the other (preceding) train - both trains adjust their driving dynamics with decreasing distance - which does not fit the asynchronous driving dynamics model of FBS.

Up to now, "moving block" could be simplistically modeled with very short, but fixed block distances, which also fits quite well with some practical effects.

  • "Moving block" is not much better than stationary blocks, if the block distances become shorter than the braking distance. The braking distance of "normal" trains normaly measures a few hundred meters.
  • It is already technologically foreseeable that the train integrity check / signal transmission from the vehicle (always somehow necessary for "moving block") will not really be possible "dynamically" at deterministically short intervals, but will be influenced by stationary components - such as locating balises or radio masts or transmission distances. All this speaks against a real (theoretical) "moving block".
  • The aim is usually to distribute the time slots evenly, but not to concentrate them.

Therefore, experience has shown that there is a saturation limit at about 90 seconds of train following time, which you can't get far below anyway. And the 90 s can be reached quite well with short stationary block posts.

The virtual "block signals" (block markers) do not have to be entered individually, but FBS offers a special function with which they can be distributed automatically at regular intervals on the corresponding route.

This function ("Insert block posts ...") can be found in the input window for the infrastructure data on the register page Stations& Locations at the bottom right.

Last update on 16.07.2020 by iRFP Support.

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