Hi all,
With the advent of
speed indicators for Ks signals thanks to ywang, it is time to rethink the way speed limits are currently handled in the interlocking system. This issue was identified in the developer conference.
Real-world railways (especially here in Germany) actually know three types of speed limits:
- The general maximum permitted speed of the railway line ("line speed", a global speed limit)
- Permanent local speed restrictions (due to switches, curves, other circumstances - until the end of the dangerous section)
- Temporary local speed restrictions (due to construction works or track defects, typically the signals for this are not fixed in place)
For reference, the "official" document specifying railway signals in Germany is the
Signalbuch.
I want to rework the speed limit signs, so that they are more consistent with the German signal spec. Also, I want to add a way to set the permitted line speed so that it can not be overridden by signalling. Here is my proposal:
Permanent local speed restrictions
All the speed limits in advtrains currently fall in this category.
For the Ks signals (now with speed indicators), they follow the spec pretty well:
Using the new speed indicators, you can now signal different speeds for different routes (such as slower speed for diverging route)
The Speed Limit Signs however do not adhere to the Signalbuch. The correct signal shape would be Zs 3:
and Zs 10 for the "End of speed limit" sign:
I therefore suggest to
change the shape of the current 8,10,12,16 speed limit signs to the Zs 3 shape and the shape of the E sign to the Zs 10 shape. This happens without changing the node name so that existing signs are automatically converted.
Together with this, the non-Ks light signals should again have the function of lifting the local speed restriction, as it used to be until about 1 year ago.
Line speed
IRL the line speed is fixed and published by the railway company in operation instructions. The train driver has to look it up or memorize it. This is of course not feasible for advtrains. However I have observed that on some railway lines (e.g. the line Dresden-Görlitz) the "Lf 7" signal is used to tell the permitted line speed (120 km/h):
I suggest to
add a new set of signs in the style of Lf 7 (= the current sign model) to set the permitted line speed. The line speed is independent of the local speed restrictions and is not changed by light signals. It is only changed by another Line speed signal, setting a new maximum line speed.
Temporary local speed restrictions (optional)
For construction works, Germany has the "Langsamfahrstellen-Signale". They look like this:
To make adding those temporary speed restrictions possible in advtrains, we
might add a set of signs in the style of Lf 1/Lf 3. They would not interfere with the line speed or the permanent speed restrictions.
In summary, the resulting permitted speed would always be the minimum of line speed, permanent local speed and "La" speed.
Please tell me what you think of this proposal, and feel free to discuss it.
- orwell