Factorio Forums

Underground rail would be a new thing to add to the game. At least for regular straight track so that tracks can cross other rails, belts, and buildings with ease.

I agree.

However, I see the following problem:

Since the train can run out of fuel at any moment and therefore can get stuck inside a tunnel, the player must have some way of going into the tunnel to rescue the stuck train. This would require an underground view to be implemented. I imagine that this would be a lot of work.

Rail bridges would solve the issue better than undergrounds IMO due to the nature of hidden surfaces--you could tear down the bridge and get underneath it again (if that were even needed, since it would be a small width), but there's no reasonable way to add 'digging' to get into a tunnel.

Both are unlikely to be added, however.

Not sure if it is feasable - a tunnel that would be destroyed with a vehicle inside would be troublesome to handle. Bridges might be a better idea - could be implemented as just another type of railtrack without collision detection with standard track objects while the train is on it. It'd also make intersections a lot easier - you could make the standard highway cloverleaf without actually intersecting tracks.

Added to viewtopic.php?f=80&t=14024#p128695 Travel over Water: Boats, Ships, Canus / Bridges / Tunnels

Travel over water would certainly be a welcome side-effect, though less significant now that landfill is even included in vanilla.

After thinking about it a bit more, I guess tunnels could be implemented the same way as in OpenTTD.

A train will never get stuck inside a tunnel, for example it will never break down (i.e. it cheats while inside a tunnel). In Factorio, this would be equivalent to a train never running out of fuel while inside a tunnel, or, even if it does, it will cheat and still be able to keep up enough speed to leave the tunnel.That way, the player will always have access to the train in order to feed it additional fuel.

Tekky wrote:it will cheat and still be able to keep up enough speed to leave the tunnel

You would have to disallow placing underground exits and entrances too close to each other. Otherwise, I could create a train that runs without fuel by exploiting this.

Am I wrong for just wanting a simple Underground Belt-Esq Rail?

I mean really. Am I asking too much? *Potato quality photoshop

It would be way too OP, as it would either subvert or trivialize intersections. You have signals for a reason, and the devs want you to use them, not subvert them.

How about a bridge over water?

Moved to ideas and suggestions

Given an inclination of 10 degrees, the horizontal length of the hill needs to be around 6 times the height. You can't really make train track steeper than this. To get a train under level ground you need a long slope!

A long slope would be perfect actually if it would be combined with long bridges / tunnels.

1) Simple cross roads would be far simpler since they don't need the slope so bridges would not make cross roads obsolete.
2) Long bridges/tunnels would allow crossing larger factories parts or water with the drawback that you can't have a train stop near them (no train stop on the bridge/tunnel or slope).

I think that would balance out nicely.

I do see other problems though. What to do when the player exits a train on the bridge/tunnel? What if a train runs out of fuel in the middle? What if 2 trains enter a bridge/tunnel from opposing sides. There has to be a way to reach the train and to enter/exit.

leoch wrote:Given an inclination of 10 degrees, the horizontal length of the hill needs to be around 6 times the height. You can't really make train track steeper than this. To get a train under level ground you need a long slope!

We dont put this much thought into belts or pipes...no reason to do it for trains.

This has already been suggested less than a month ago in the following thread:

viewtopic.php?f=6&t=44338 Underground rails

EDIT: Meanwhile, the threads have been merged. Therefore, my above link is now invalid.

EsX_Raptor wrote: ↑

Fri May 05, 2017 10:05 pm

Tekky wrote:it will cheat and still be able to keep up enough speed to leave the tunnel

You would have to disallow placing underground exits and entrances too close to each other. Otherwise, I could create a train that runs without fuel by exploiting this.

Good point. I guess if the train is able to "magically" leave the tunnel despite being out of fuel, it should be "magically" prevented from entering another tunnel, to prevent the exploit you mentioned.

Tekky wrote:This has already been suggested less than a month ago in the following thread:

viewtopic.php?f=6&t=44338 Underground rails

People like to throw general discussion threads into suggestions with no regard...

NiallTorint wrote:It would be way too OP, as it would either subvert or trivialize intersections. You have signals for a reason, and the devs want you to use them, not subvert them.

I disagree that they would be OP, or trivialize intersections. Sure, it trivializes simple crossovers, but it opens up design space for junctions (especially if there are drawbacks, like lower maximum speed on bridges and low slopes to force bridges to be long). It would offer a choice: build a compact flat junction with tricky signalling and blocking, or build a grade-separated junction that minimizes conflicts and is easier to signal but adds a slowdown to some paths even if there is no other traffic nearby and requires much more space.

i think there was an underground rail mod a few years ago, but it could have been implemented much better. Try posting in the "request for mods" section? modders look there there regularly to get ideas for mods. Devs are mor likely to implement a feature if it's working really well as a mod