Thinking about making a small modification to the tutorial.
https://github.com/simutrans/simutrans/pull/3
Github pulls will be ignored. Anyway, you implementation was awkward, calling a tool for such a simple, even local function. I have put this in the API, r11216
wow I didn't expect you to use "sint32", I guess it's a substitute for boolean variables.
Line 369:
* @returns true if convoy is currently waiting (for way clearance)
The description is wrong.