Company Liquidation (and game-crash)

[jeffryfisher]

Last night I got into a bind where my saved game would consistently crash RT2 a few moments after restarting the clock. The save was in mid December. Since there was a motion-freeze before any end-of-year events, I knew that the game was trying to do something complicated with an AI company (such as build track). Since the crash occurred before my events, I figured that the action chosen by the AI caused the crash.

 

My investigation (and about a dozen reloads) revealed the problem:

 

After futilely poking at many odd joints and ends of AI companies' tracks where builds might occur (in the forlorn hope that I'd disrupt the bad AI decision), I finally happened upon a corner of the map  where my track intersected another company's track, and three of my trains were stuck waiting to get across. As it happened, the AI had a train that was "active" (hogging the track) but not moving -- a sign that it had no route to its destination. My trains were stuck with their noses pressed against this moribund AI train.

 

So my idea for stirring the pot and get a non-crash result was to build a connector to fill a gap where the AI company's track had been destroyed by an earlier event. I ran the clock, and miracle of miracles, the AI's train pulled away, and my trains began pouring through. Then the year ended, the game froze to do its AI thinking, and instead of a crash all hell broke loose.

 

This AI company had been the sickest of the sick companies still on the map, and it had picked this year to give up the ghost. Because of my game settings, its track was being deleted from the map (along with my three trains). RIP!

 

Apparently, in its prior configuration, my trains' noses were so delicately balanced on the edge of the AI track that the deletion did not kill the trains, but the absence of track under them crashed the game. This then becomes the latest in a whole constellation of game bugs that crash the game by somehow producing a train without track under some part of it.

 

For the curious, the easiest such bug to reproduce is the one where a naked engine pulls into a station, then you pause the game and delete the track it rode in on. Then you tell the train to pick up a few cars of anything, and then you restart the clock. As soon as the train puts on cars, it tries to put them on the track it rode in on, but that track is no longer there. The game crashes.

 

Another such bug, much more difficult to reproduce, but virtually the same one I encountered above, is where an event deletes track in an area where trains are moving. There's a fine line between the point where a train gets deleted with a segment of track and where a train decides that it can go forward rather than reroute by bouncing.

 

Unfortunately for the game, a train in motion can be beyond its fail-safe point and still not be deleted when the track in front of it vanishes. The timing is thin, but if you get "lucky", a track deletion event can catch a train on the edge. The train will then run off the end of the track and crash the game. The work-around is to program all track-destruction events to also contain the train-stop effect. This keeps them out of danger, but it also means that a trailing event needs to restore train-move rights if/when you want rebuilt track to be usable.