Outside Train Connections Observed Train Behavior

This guide will serve as a running train of thought (pun intended) for what I have observed so far with outside train connections.
I build maps. I love doing so. I am an asset and mod junkie as well, but when I build maps I try to use only vanilla assets and settings so the majority of folks don't need to install things to play, but can add to it if they choose.

Everything below is based on vanilla assets and vanilla statistrics with comments when a mod is in use.

This is a Work In Progress and I will edit this guide from time to time with Updates.
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If you find an error, omission, or want to add something please post comments.

Please RATE UP if you find anything in here of use to you.

Maximum Outside Connections

• 4 Connections, which can be anywhere on the map edge.
  
• If the connections are within one tile of each other they share spawned vehicles and passengers. If you separate the connections by one tile you can get the maximum number of vehicles and passengers to spawn.
  
• You can have more outside connections using a mod.
  
• You need at least two outside connections per line to generate outside train traffic. Although the connections show in/out arrows, in reality the spawning only happens when the trains can travel from one outside connection to another.
  
• The net effect for vanilla play is the maximum number of train lines that spawn traffic on a new map is two. Place them accordingly.

Observed Train Traffic Prior to Placing any Stations for Passenger or Cargo

• Cargo and passenger trains will travel all lines randomly. This is called Dummy Traffic and can be adjusted by 'Configure Outside Connections' mod.
  
• Tunnels created in a map editor show up in game play as 'Buried' until you unlock the tile during game play that the tunnel is in. But trains don't care, they will go right through it. It is cosmetic and a flaw in the game.

Observed Intercity Trains Behavior for Passengers

• The first Intercity station to connect to an outside connection will cause that connection to spawn external passengers for the duration of the game. It is the nominated passenger line.
  
• Any other outside connection will never spawn passenger trains. In other words, if you have two separate outside lines and place an intercity station on one, and then place an intercity station on the other line, the first one gets all the passenger trains and the second never does.
  
• If you connect separate outside line connections to the original working-nominated outside passenger line then outside passenger trains will travel on those lines, but spawning is shared and cut in half. In other words, taking the example above, if you connect the second outside line to the first, then the second intercity station will get outside trains, but the spawning rate will be shared and random.
  
• Once a line has been nominated as a passenger line, if you don't have a cargo station on that line you wont see cargo trains on it. Even dummy cargo train traffic.
  
• There is a side effect to connecting separate outside lines. See cargo trains below.

Observed Cargo Train Behavior

• Same rules from the Observed Intercity Train Behavior apply here for cargo trains. See above section, with one caveat. Cargo stations do not have the ability to 'Untick' intercity trains. Unlike Intercity passenger trains, external cargo trains will find all your cargo depots and travel to them randomly. Choose your locations wisely, there are plenty of guides that describe good train traffic placement including one creative one that describes isolating a cargo station with a harbor. No need to re-write those guides here, just search for them.
  
• If you nominated the original passenger line for cargo by placing a cargo station on it, you cannot get external cargo trains on a separate line.
  
• If you have a separate outside line for cargo and a separate outside line for passenger (with placed stations) and then connect the two separate lines you can expect cargo trains to exit the map on the passenger lines randomly, contributing to train congestion on that line. The reverse is also true for passenger trains on cargo lines, expect congestion. Just don't do it.

Spawning your own trains to take passengers and cargo Out

So far I have been describing the games spawning feature for bringing passengers and cargo inbound from someplace else. You can spawn trains to leave the city but cargo and passenger trains act differently here is the difference.

• You can spawn external bound trains from any station that has both an external connection and has 'Intercity Trains' turned on. The trick is, you need passengers to want to leave via that route.
  
• The first station plopped that caused the line to be nominated as passenger line gets preferred status. In other words you can have two stations equidistant from the edge on the same line both marked as intercity and the cims will always travel to and queue up at one station for an outside ride, causing trains to spawn only on that track. There is nothing you can do to affect that. Moving the stations farther away from each other and even to different section of your city with different districts will not change that either. Keep that in mind when placing your main station.
  
• Cims will leave the city at any intercity station if a train arrives from outside to drop off passengers and the cims 'detect' its coming. That as you can tell is hit or miss, so don't count on it.
  
• Cargo trains are different. If trucks detect two outside capable cargo stations they will choose one that is closer.
  
• You can artificially influence which cargo station a truck will use by placing it closer to its factory. This leaves you with a cool load balancing trick, read on ...
  
• If you have one cargo station near some factories that has a conga line of trucks waiting to dump goods, you can speed this up by following these rules ...Place another cargo station directly across the street and line up the 'despawn' points. Those are the points where the trucks enter the building and disappear. You also need to make the stations somewhat equidistant from the factory. You need a one way road between the stations so your trucks don't need to cross the street. (A two way road means the trucks need to travel longer and uturn at the intersection which means it is not equidistant. Last rule, the stations need to be connected to the same track nearby each other. The effect should be a 50/50 split of traffic. Just give it some time to equal out since the pathfinding engine needs to update all the new trucks.
  
• The above trick will cause equal spawning of outbound cargo trains making it more important to separate your cargo traffic from passenger lines.

Fixing external Connections

Some things I have done to fix unexpected behavior:

• If you unintentionally connected two train lines delete that connection and wait for all trains to despawn or move off the map before making any further changes.
  
• If you placed your first cargo station on a passenger line and didn't want that traffic on that line, remove all cargo stations from the line and wait for the cargo trains to despawn, or delete the cargo trains from the line.
  
• Same for passenger trains on cargo lines, delete the stations and wait or delete passenger trains on that line.
  
• If you want to swap nominated passenger train lines you need to uncheck all intercity radio buttons on the train station on that line, wait till all external trains despawn or delete them and place an intercity station on the new line and wait for one external connection.
  
• Worst case scenario if none of these fixes work, delete the last bit of track on all external lines. The last bit that goes off the edge of the map is technically a train station. You can tell by the criss-cross tracks. Wait for all the trains to despawn or delete them. Make your changes to all the stations and then rebuild the last bit of external train tracks one line at a time until you see the effect you are looking for.
  
• If you see trains 'derailed' at the edge stations on the map the problem is the connection going off the map. Some trains, especially those really long cargo trains have a difficult time spawning on edge if the train track in not straight under it. This causes congestion. To fix this, delete any external connection that does not have a few blocks of very straight track at the edge, then draw new track starting from outside the map back to the existing track making sure you draw it perfectly straight. It needs to be as long as your longest train in your assets.

Paused Train Tracks - No Trains Spawning

Ever see your train stations idle and wonder why no trains or cargo is coming or going? Cant figure it out? Don't understand why? Here it is ...
What does it look like? When you zoom into the external connections at the edge of your map you see a Button flashing over the connection with a red circle and line over a 'play' symbol. That means you are hosed for that connection. No amount of changes seems to fix that, but here is a solution.
I have seen the effect after playing a game for a long time happen and I cant figure out what causes it. It could be anything. A quick scan of help forums you see a lot of people affected by this issue. Once an earthquake of magnitude 10 shook my city so bad the elevation at the edges changed and broke all connections. CO did not give us the tools to see this or fix it. You need the mods listed below to even see it, much less fix it. In any case it could be anything that causes the no spawn condition. Fix ...

• Delete any connection with a Pause (no Play) symbol on it and recreate it. You just need to delete the last bit of it that runs off the map edge. See note on length.
  
• Paused connections may still allow traffic to exit, but will not allow new trains incoming.

Final Thoughts on Game Play with Train Lines

• When playing a map you didn't make, open it first in map editor and fix any train lines you don't like.
  
• Consider always keeping passenger train lines separate from cargo lines. You don't want that congestion on one line, ever, During game play it will eventually turn into a train congestion mess.
  
• Pay attention regularly to your external train connections at the edge. A quick checkup every so often will save you some grief.
  
• If you build new lines, pay careful attention to the track you select to lay. If you have a one way track option in your assets make sure you never use it for laying new lines or fixing existing lines. I have accidentally laid whole sections of track with one way track and wondered why trains where not arriving at the stations. I could see them spawn, travel along the line and then they disappear at one point. That's a dead giveaway that you have a break in the line or have a one way track somewhere. Whats worse, its not obvious that one way tracks are inline unless you zoom all the way into to the track to see the mini arrows. That means you need to inspect at close range the entire line. Big pain.

Useful Mods

• Unlimited outside connections - Gives you the ability to add more external roads at map edge.
  
• Any Road Outside Connections - Goes with the above mod to add any kind of road as an external connection.
  
• Map Editor Tunnel Enabler - Gives you the ability to make tunnels in Map editor. Not needed during game play or to use the map afterwards.
  
• Cross the Line - Use this with 81 Tiles, This mod allows you to cross the border and make changes.
  
• 81 Tiles - Use this mod to enable all 81 tiles for edit.
  
• No Border Camera - So you can see what's outside of the border of your city.
  
• Configure Outside Connections - Modify spawning rates for external connections.
  
• Clouds and fog Toggle - Turn off edge fog so you can see what your doing on the edge of the map.
  
• Network Extensions 2 - Gives you tools to make train lines at the edge of the map.

[junglelands]

No other map comes close to this map. Just Brilliant.

[nihilco]

Perhaps this is more of a map-maker thing than train behavior, but still... maybe you can add the following fix?

Problem: outbound trains clog up the train lines all the way up to the map's edge.

Cause: the last node on the train track before the map's edge is too close to the edge, not allowing a full train-length.

Solution: move the node further from the map's edge, simple :)
To achieve this, you need a mod that allows changes outside the vanilla tiles + MoveIt or NodeController.

Pro tip: if you use custom trains, make sure to give them enough room when you move the node. They can be longer than the vanilla trains.

[stefmikhail]

This is brilliant however I am curious: I created my city small and it has grown so I have replaced the original passenger station: If I delete all stations and place a first one again, will it reset the receiving of passengers etc? It's rather frustrating that I now have no out passenger train travel in my city, and the goal of my city was to emulate the era of train travel.

[chad.d.flowers]

0h

[SkiRich]

If you already straighten out your tracks then it sounds like game save corruption.

[chad.d.flowers]

what?

[pharaoffm]

I have a problem where the array index is out of range error apears instantly when a passenger train spawns on the tracks at the edge even though the tracks are straight. Also this train is dummy traffic. All the passenger trains semm not to recognize my stations. Cargo trains run smoothly. any idea what causes this? I already tried disabling mods but the errors stays.

[SkiRich]

Traing tracks have diirection. Check all your new track and make sure everything is right.

[rectorsquid]

Very informative. I just wish it would explain why when I delete some track from a fully functioning cargo station to attach it instead to a rail line that has it's own outside connection with no other stations, that no outbound trains get generated by the cargo station. The new outside connection has the little arrows and everything looks good. But the cargo station doesn't seem to like having it's own new outside connection.

[SkiRich]

Not sure. Never tried that. Try it and let us know. My initial reaction is no, but then you have to think of the fake traffic engine and how that works.