View Full Version : Very Basic Signals Question - needed?

May 30th, 2013, 07:59 AM
IF you are NOT driving a train but have an ALL AI scenario is there ANY need for signals. That is, do AI trains ever "look" at a signal or do they strictly operate from dynamic rules that are adjusted as the scenario progresses?

May 30th, 2013, 08:09 AM
I use all Ai sessions and they do use/obey the signal aspects. No signals would give you half line speed all the time, if your lucky.

May 30th, 2013, 08:57 AM
Ah, very good reason to use the. Thanks

May 30th, 2013, 09:20 AM
I believe that AI traffic is controlled by junctions, not signals.

Signals show if the track ahead is free or if it is terminated by another signal or portal. AI drivers move from one junction to another. As the maximum radius size for junction trigger is 500 meters only, AI drivers see only few junctions. They don't understand concept of a block and there is no need for it, because Trainz default engine does not provide one and implementing it by a script would mess up the simulator completely. A small station with 4 load/unload tracks, capable of servicing trains up to 500 meters long would typically have entering signals at both ends separated by distance of about 1500 meters. No AI driver can "see" what is the status of the junction at the other end. So, signals act like proxies to junctions, but they are not in charge.

Despite this limitation, signaled track has number of advantages when driving in AI mode:
- It allows dispatching more than one train along bi-directional line. Without signals, the entire map is like a single, gigantic block, managing which can be unpredictable.
- It allows terminating end of track. If end of track is unprotected by a signal, AI driver may attempt to drive forward and derail the train.
- It allows to set the stop point before junction. I usually place a signal 100 meters before junction in main tracks. If for some reason AI driver will not apply break on time, there is still some distance left.

I am pretty sure there are many other good reasons, of which I can't think right now. Generally, you should know limitations of AI driver and signal your route accordingly.

May 30th, 2013, 11:28 AM

AI and player trains will scan the track for approximately 6 miles ahead on their route looking for trackside objects. If you use one of the enhanced HUD rules which shows the distance to upcoming junctions, signals and speed limits you will find that these do not show unless the train is within about 6 miles of them. Scripted signals such as those from JR and bloodnok work using the block system in later versions of trainz. The semaphore signals on the add on Settle and Carlisle route also work correctly using the block system. Most problems with signalling are usually caused because they have not been set up correctly.