[0.17.16] All your train are belong to us

[mrvn]

In a PvP game the train network and trains of players can be mixed up. Sorry for putting multiple bugs in one report but they are all train related and probably need to be fixed (or marked as intended behavior) as a group. I've tried to order them by severity as I see it. So it might be the first few will be Not-A-Bug while later are.

1) Train tracks from multiple players connect.

While train tracks from multiple players connecting might make sense this already allows one player to seriously screw up another players train system by breaking the signaling.

2) Train tracks from one player can be constructed through a closed gate of another player.

The gates should probably stop construction.

3) One player can add signals to another players tracks.

Again, this easily stops the others players train system dead. And the other player can't even remove the signals.

Note: I didn't check if stops can be added. I'm assuming they can be added too.

4) Trains from one player path to stations from another player.

If one connects to the others player train tracks and knows the name of a station one can add second station with the same name. Trains will then go there if that station is nearer or the other station is disabled. This allows stealing trains.

5) Inserters can remove items from other players trains if they are at a stop.

One can't take anything out of other players chests or even from belts so this seems out of character.

Note: An inserter or player can put items on another players belt but not into chests. Bug in belts?

6) Other players trains can be highjacked

A locomotive, cargo wagon or fluid wagon can be added to a train. The train then turns of automatic mode. While the player can not enter another players train the added component belongs to the player and can be entered. The train now belongs to two players. Adding a locomotive allows changing the schedule or putting the train back on automatic.

The direct consequence is that the train can be redirected at will. Since part of the train belongs to the other player it will open gates as long as it approaches the gate with a component of the other player at the front. So a train inside a wall near the wall can be highjacked and used to open the gates and drive the train outside. But further this allows the player to sneak into the other players base.

7) Placing a locomotive, cargo wagon or fluid wagon between two trains connects them.

With bi-directional trains one can destroy a wagon in the middle and replace it. That way both ends of the train still belong to the other player allowing them to open gates in both directions.

8) Turrets don't always attack other players trains.

In the save on of the trains gets attacked by turrets in the southern base but the trains don't get attacked in the northern base. Not sure what causes this but it might have something to do with adding a new component to the front, middle or back.

[Twinsen]

These are all pretty much intended or minor issues. We don't plan to go super far with force separation implementation.
Being able to use and interact other player's trains leads to more interesting and fun situations. These are all considered valid tactics.

Turrets don't shoot trains because they are not military buildings. Otherwise biters would attack trains and that would lead to many unwanted situations.

[mrvn]

These are all pretty much intended or minor issues. We don't plan to go super far with force separation implementation.
Being able to use and interact other player's trains leads to more interesting and fun situations. These are all considered valid tactics.

Turrets don't shoot trains because they are not military buildings. Otherwise biters would attack trains and that would lead to many unwanted situations.

Hmm, but they did shoot one train till they run out of ammo. Maybe they didn't shoot at the train but at the driver (me).

[Klonan]

Yea, most of these are not really bugs. If you don't want players using your trains, put a turret or wall there to stop them.

There is also the case, i think which is more common, where two players are on other forces, but are friends with each other,
So sharing rails, trains, stations, is all intended as part of a cross-force collaboration.

The only thing I would consider fixing is #2:

2) Train tracks from one player can be constructed through a closed gate of another player.

Since this can be used to cheese through gates without the other team noticing.