How may one limit the range that AI can 'see' the next speed limit ahead?


Active member
I am trying to land an AI Boeing 747 on a 10,000 foot long runway and make this landing appear natural. The trouble is, AI sees the 10 mph speed marker at the end of the runway way too soon. He has to slow down there, of course to turn on the taxiway to exit the runway. A Boeing 747 should touch down at about 140 knots/160 mph and gradually slow toward the end of the runway. I am using aircraft train vehicles by vulcan. My "pilot" slows the big jumbo jet down to under 100 mph well before touchdown sensing the low-speed marker about 1-2 miles ahead thinking he is driving a heavy freight train on a steep down grade. In the real world, the plane would stall short of the runway, crash, burn and I would die as a passenger!! :'(

I need a method, driver rule, config edit, and/ or asset that basically tells AI to not brake so hard so soon. I want to keep the vehicle speed up higher until AI gets closer to the slow-speed marker. He should only start braking considerably about a quarter way down the runway.
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If this is for TS12, you might want to take a look at some of the options available for the trainzoptions.txt file. You can check the Wiki at the top and also do a search in the forums for it, which may bring up an older thread. There's one put together related to all the available options for the file. Keep in mind that doing this may confuse things and cause unexpected results because these settings are global and not just for a single signal setting.

For your airplanes, you might need to use multiple invisible type 05 (permissive signals) spaced out ahead of each other to keep the AI planes from stopping in mid-air or slowing down.
This is for TS12 in my case but I don't want global rules for plane speeds applied to ordinary trains on the same map, of course.
The planes slow down before touchdown because they sense the upcoming speed limit marker at the end of the runway, I believe.

What mechanism in the game governs the distance AI sees and/or reacts to a speed-limit ahead anyway?

The "plane" train vehicles do drive at considerably higher speeds "in the air" than do proper railroad trains on the ground for realism.

I don't know if permissible signals will make the AI driver overlook the fact there is a 10 mph marker 10,000 feet ahead near the end of the runway in regards to delay of braking. Ideally, I would like to keep the game's AI mechanism "blind" to the upcoming low-speed-limit track mark until the train vehicle is within about 5,000-7,000 feet of it. AI often likes to anticipate things way up the line ahead. In a way, the airplane should be taken by surprise when there is and indication to slow down ahead once all its landing gear wheels are squarely on the runway.
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Yes. Even put one for 300 mph 500 feet BEFORE the one that said 10 mph at the end of the runway by the runway exit as a test. AI sees right through it like an X-ray camera. Still slows down below stall speed before touchdown. AI always reacts to lowest speed limit sign within a certain range ahead, perhaps two to five miles. The trick is to make AI more short-sighted for speeds ahead. Clever content designers know how to "fool" the game's engine to "violate" certain built-in/hard-wired rules and game operating principles to get the desired effects for specialized assets. Aircraft are rather special since Trainz is a RR-dominated environment.

Vulcan developed these aircraft train vehicles as an afterthought. No serious specialized content for command and control was yet designed to compliment them to make them act realistic although there may be some good stuff coming down the pike to make Trainz planes act more realistic. Trainz game designers never considered realistic aircraft simulation. Most Trainzers with airplanes as moving scenery on their maps probably just have them circling around in the sky anyway with no serious intentions of making them operate like real-world aircraft.

Again, my dream is to ultimately have a PC-based or X-box/console-based vehicle-driving/map-building game with world simulation that accurately simulates a variety of transportation modes (trains, planes and automobiles) each according to its own real-world rules and physics principles all "under one roof", so to speak.
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AI always reacts to lowest speed limit sign within a certain range ahead, perhaps two to five miles. The trick is to make AI more short-sighted for speeds ahead.

Are you smoking weed or something while playing Trainz, coming up with these incredulous conjectures? AI reacts to the next and ONLY the next speed limit within the default or defined autopilotsignal distance unless under a caution aspect, for which it will maintain half speed. Also check out this thing called Flight's very realistic I heard. At least the 747s there don't try to land at 260 knots.
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No, I am trying to make mine in Trainz land at more like 160 knots. It seems, without the knowledge and sophistication of a total PC geek or software engineer, I would need a runway about 5 miles long to do this just so the AI does not detect the upcoming slow-speed marker at the end of the runway too soon. But a runway five-miles long is totally absurd. AI likes to land train-vehicle aircraft at about no faster 95 mph (83 knots) with a 10 mph sign 10,000 feet ahead. Obviously, they can't exit the runway to the taxiway going too fast.

The caution aspect does not apply since there is not one signal on my entire airplane loop. I should mention there are turnouts on my taxiway for planes to pull onto the apron dead-end sidings to park. What is the range for AI to sense upcoming junctions? Is the "pilot" slowing down to react to upcoming switches instead of the speed signs?

I could do an experiment and delete these switches and see if AI behaves differently.

Yes, I don't fully understand Trainz on the inside: all its internal parts that makes it tick.

I am using TS12 with that dinosaur of a Jet game engine that people put down but I'm trying to fly "jets" in it, no pun intended. I gave up TANE a month ago because the audio properties in that game are horrible.

I have MS Flight Sim X. It sucks because there is no "Surveyor" to build my own world and there is no railroad train scenery on the ground to boot. The aircraft do fly, land, take-off, taxi and park quite realistically, however. There are random AI planes, not interactive with human game players, flying passively in the background also as well as automated random cars and boats on the surface.

There are no AI drivers/pilots in Flight Sim either to program schedules for or issue commands to. I either have to watch random game-generated scenery game planes in the background or fly my own plane, which I can choose, along with an airport in the world, with my hands on the controls or set on AP. The route, map or "plane board" (not user editable) is literally the entire world.
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1. 300mph is 260kts. If you're looking for "realism", attention to detail is a good start.

2. I just told you dammit; AI will only detect signals and speed signs as far ahead as the autopilotsignaldistance which is 200m by default. If it's behaving any other way you're doing something wrong.

3. You have no signals on your route but complain when vehicles do not stop where you want them to? Okay.

4. No, none of us knows how Trainz works "inside". All we do is understand and properly apply rules and commands instead of barging headfirst into everything like a bull in a china shop and asking a hundred questions afterwards "why is everything broken".
I only put that 300 mph sign on the runway (near the end of it) as an exaggerated test to see if it would offset the AI's tendency to slow down way ahead of time in reaction to the 10 mph sign at the end of the runway.

The 300 mph sign has no effect on AI landing speedwhatsoever. The speed-limit set for the approach to the runway is set at the metric equivalent of 160 knots or 296 KPH.

You tell me why the plane is going much slower than the speed-limit sign it just passed?

I have not done anything to the autopilotsignaldistance configuration whatever the devil that's all about.

What I am going to do now is remove that 10 mph sign at the end of the runway and see what happens when I try to land at a higher speed.

As far as signals go, I have already tried many different ones and they don't work on my plane loop. They stay stuck on red and AI can't ever drive past them.

I am down to trying to fly just one plane on my loop after earlier attempts of multi-aircraft operation failed miserably. I am no Einstein or Thomas Edison of Trainz as far as technical smarts go, for sure.

If push comes to shove, I'll just put up my 747 touching down at 95 mph. Perhaps, vulcan or others will come up with specialized rules and content later on to better manage Trainz-based aircraft operations for realism. Vulcan's Aircraft Action Trigger which I am now using to control flaring (nose-up attitude) for touchdown and wheel squeal/tire smoke on touchdown is still a WIP, I gather. He has indicated that there are additional functions for this trigger in the works. He has yet to publish all of the trigger's functions at his website. I only know a few of them. No big deal. The 747 is a big plane and they look like they are going slow in the air anyway because of their enormous size.
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Some here complain that the TRAINS in Trainz don't behave realistically enough and you want airplanes to behave realistically? You may have to do a better job of suspending disbelief and take what you can get, at least until someone does create that "world simulator" you are looking for.
There is some reason why a plane, or loco, does half the speedboard speed ... But I forget why

You would probably do better if you first lay your airplane path on the ground, and get it running correctly there, by placing signals and speedboards on track laid on the ground ... placing these at 2700' would be difficult.

Using AI, you will always have stopped, or stalled airplanes, that are waiting at green signals, waiting for track authorization, only to back up a mile, and restart the same identical malfunction ... as a turnout, or a plane waiting to take off, is blocking it's path
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There is some reason why a plane, or loco, does half the speedboard speed ... But I forget why

AI reacts to the next and ONLY the next speed limit within the default or defined autopilotsignal distance unless under a caution aspect, for which it will maintain half speed.

I have been using Invisible Speed Signals on my airplane layout. Could this cause undesirable slow-speed issues?


author: bpanther

Deutsch: Unsichtbares Speed-Signal v2, auch fuer Weichen. Beschriftung erfolgt automatisch mit Angabe der Geschwindigkeit und Weichenstellung. Es koennen nun mehrere Weichen als Pfad angegeben, Prioritaeten benutzt und Regeln erstellt werden. Eine Auswahl, ob die Geschwindigkeit nur fuer die KI oder auch fuer manuell gesteuerte Zuege aktiv sein soll ist ebenfalls moeglich.
English: Invisible Speed-Signal v2 for Junctions. Automatic Signalname description from SpeedLimit and Junction. Now with using of train priorities, if speed limit valid for AI or/and manual trains, rules and more junctions as path possible.
These might. Try "regular" invisible signals, if there are any, and see if that might help. The ones you are using sound a bit specialized.

Those specialized speed signals I have been using all along do work great once the planes take off and are up in the sky airborne and cruising. I use one on the runway too set at high speed for take-off. The nice thing about them is that you can customize the speed settings for them. The Boeing 747 by vulcan raises its landing gear at 240 kph and lowers it just below 240 kph by default. I can edit this parameter in the airplane's config.txt as well to have a higher target speed for landing gear/flaps actuation. I would prefer landing gear to be actuated by a track trigger, as vulcan's own Aircraft Action Trigger, rather than by speed if I had my way. I need to set the speed at 235 for approach so the gear comes down before landing. The airspeed I use at cruising altitude is 375 kph, tops, as the curves in the sky track are too sharp to practically support any higher airspeeds. I don't want the plane unrealistically bank too hard in the sky. They might not be so hot for the runway and taxiway.
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Well, the same thing happens when "regular" invisible speed boards are used. What I have been trying to do is have the AI-commanded plane land at realistic speeds, slow down toward the end of the runway to turn to exit it, then pull on to the apron off the taxiway parallel to the runway and stop at a track mark using the Drive To command. AI anticipates having to stop ahead and slows down below normal aircraft touchdown speeds well in advance. Drive To track marks ahead take precedence over any speed signs ahead. Navigate To the track mark at the airport has the same undesirable slow-down results too. The same thing happens when AI is commanded to Drive To the Hold Short of runway track mark without ever using a turnout. Commands resulting is stopping the plane ahead cause braking far in advance. The only way that I can have the plane land at realistic speeds is to never have a command in the schedule resulting in stopping the vehicle anywhere at the airport. The plane would have to land and keep moving on the ground back to the runway to take off again using a series of Drive Via commands and then the AI drivers heed the upcoming speed signs accurately.
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I would think that all the fun of flying a plane in MSFS, would be operating the controls manually, just like real pilots do. And watching in Cab view, freeroam view, or tracking view, Real pilots do have computer controls to computer control assist flaps, and steering ... but they do not have AI.

Most of your problems result from trying to use AI, which does not always act the way you want it to
I only put that 300 mph sign on the runway (near the end of it) as an exaggerated test to see if it would offset the AI's tendency to slow down way ahead of time in reaction to the 10 mph sign at the end of the runway.

You don't need to understand the internals of the application in order to work out where the problem might be. You only need to think about what the AI has to do.

Consider the possibility that AI looks ahead and considers all speed signs on the track. Are you sure that the loco dynamics allow it to slow from 300mph to 10mph in that distance? If AI applies maximum braking can it get down to 10mph in time? Perhaps it is being too clever for you and only travelling at a speed it knows is safe for the braking ability. You know that these lcoos have not been optimised for this usage, so this sort of possibility should be obvious.

What I am going to do now is remove that 10 mph sign at the end of the runway and see what happens when I try to land at a higher speed.

Start from an assumption that if the speed sign works in one case it is going to work in all other cases, and experiment to find why that seems not to be happening Ask yourself 'what's different?'. For instance, are you using a speed sign instead of a speed limit (not all signs impose a limit)?

Removing or changing the 10mph limit is a simple test you should have done before you even considered posting a query here.
Exactly, Trainz AI was not designed with aircraft in mind from the get-go. Some clever aftermarket content creator would have to develop content optimized for best aircraft behavior that is adapted to run on the Trainz platform or engine.

I could have a session where I am flying the plane by hand. Yes. I would then have complete control and speed accuracy. The idea is to have planes running continuously, hands-off, as flying scenery, however, to impress people who are not Trainzers.

Simulators are all about creating the illusion that what people are seeing on the PC screen "seems real".

Trainz is mere image and sounds: illusions.

A "normal" ground train is what I really want to drive by hand but I want a few AI trains, set to run continuously, running passively on the ground too as scenery. AI does have its faults but it still does handle trains as "trains" much more efficiently than it handles trains masquerading as "airplanes". Real trains and real planes have their own separate rules and physics principles that governs how they react in their each and own respective manner. In the real world, d/e-powered freight trains move much slower than jet planes. Jumbo jets still do stop much more abruptly, over a considerably shorter distance, once back on solid ground following touchdown than heavy freight trains normally stop from their highest speeds. Those aircraft are much faster but also much lighter.

I will just have to forgo some of the aircraft sophistication I was hoping to implement for now and just have a single plane moving non-stop on a continuous loop. No pulling off the taxiway to load/unload passengers. No holding short of the runway for departure, etc.
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Your route should not be a closed "DogBone" shape, where paths overlap, with conflicting junctions ... manually controlling planes to stop, by "Drive To Trackmark" placed prior to entry points, to the takeoff runway, would stop collisions, and Mexican standoffs.

A control tower tells each flight when it is safe to enter the takeoff runway, and you are the control tower operator ... and should not let AI run the show, as it is not perfect.

Your takeoff track, should not be in contact with incoming flights track
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