up to r6198: crash with track removal tool removing EOC

[whoami]

In http://simutrans-germany.com/files/upload/test_crash_20121218_pak64.sve (pak64), there are rail crossings with EOC signs on them. Using the track removal tool on these crossings (e.g. to disconnect the two parallel tracks from each other) leads to a crash.

I hope that the solution will not include forbidding the placement of signs on rail crossings, because I use that very often. I encountered the problem in an actual game with Pak128.

EDIT: the crossing is not necessary for the crash. It seems to happen if the removal tool is dragged from/to a tile with an EOC.

[Ters]

I want to point out that when I tried this, it didn't crash when using the track removal tool the first time, but it did crash when I tried using it again on the same tile.

[whoami]

The crash does not happen in every case, that is right.
How to crash:
- build straight track (at least four tiles)
- place an EOC (end of choose) sign on this track (not an end tile)
- drag the track removal tool from another track tile onto the EOC sign -> disconnects track and removes the sign
- start dragging the tool from the tile where the sign had stood -> instant crash

[Ters]

The crash does not happen in every case, that is right.
How to crash:
- build straight track (at least four tiles)
- place an EOC (end of choose) sign on this track (not an end tile)
- drag the track removal tool from another track tile onto the EOC sign -> disconnects track and removes the sign
- start dragging the tool from the tile where the sign had stood -> instant crash

Pretty much what I did when I tried. However, the signal was not removed on step 3. It was no longer visible, but the query tool said the signal was still there. I think that's been the case with signals for a long time. If one rebuilt the removed track, the signal would come back, but it's directions would have changed.

[Dwachs]

should be fixed in r6204