RoRo vs Terminus (was Loop vs 2-headed train network)

[ChurchOrganist]

I don't really get two-way trains... You need two lanes of track anyway so trains can pass each other and you're saving the 50 or so iron of building a loop but spending 280 on the extra locomotive. To boot, having trains constantly switch direction means no consistency with the carriages' order.

And yet this is how real life rail networks are designed - in the UK anyway, so there must be something going for them.

IMO routing is much simpler, and whilst carriage order is different at start and destination it is still consistent - you just design the stations accordingly. The only time that can go wrong is if a loop is introduced into the system.

I have noticed that using loops can result in weird path allocation by the train AI, which is why I stick to two way as much as possible.

[Deadly-Bagel]

Realistically I'm not sure trains would be able to take the same sort of turns they do in Factorio, so the loop would need to be much bigger. This isn't necessarily feasible in towns where space is a premium. I think in Australia and probably America, most cargo trains have a single locomotive and are one-way because the space isn't as much of a premium there, and towns were built with trains in mind (in these spread out areas, they would have been the lifeblood of the town) where as in the UK most towns were built before trains existed.

[Engimage]

In real life train sheds are dead-ended most of time so a train should move both ways. Also in real life this is sorted most of time by switching locomotive to an opposite train side while train is at the stop. In Factorio there is no way of doing so. That is why you have to get double-headed trains for such maneuvers.

I have used both single-headed and double-headed types of railways. Here are the major differences.

Double-headed trains can use much more compact stops. You can use a single track dead end as a stop so you can have for example a multistop loading/unloading stations where stops are extremely close to each other and also close to the processing point which is awesome for bot setups, while single-headed always need an exit route which kinda limits station designs. However with a multistop stations you will most likely want to design a separate exit for trains anyways to prevent exiting trains from blocking incoming trains.

Single-headed trains need loops. Actually most of time you can limit this only to 1 loop for every station. You do not need loop T-intersections for single-headed trains, that is a separate issue. So if you are fine with loops on stations which leads to their increased size, they will work just fine.

Loops on stations somewhat complicate train pathing and may cause trains to choose a path through the station while the main path is blocked. The more loops you make the more complex pathing calculations become causing UPS drop at some point when you get really many trains. But if you design cleverly you can avoid that for the most part.

As I mentioned loop-based intersections are much more dangerous UPS-wise than loop stations. While they do work nice and smooth on a smaller networks they will definitely hit your UPS later.

Personally I prefer double-headed trains right now just for a smaller design of outpost stations. I can't say that feeding a second locomotive with coal is a burden, trains consume really small amounts of fuel compared to anything else like plastic production, smelting or steam setups.

And as a sidenote - adding a second locomotive has a very small impact on a train speed and mostly results is a slightly higher coal consumption. You will most likely not notice the difference.

[ChurchOrganist]

adding a second locomotive has a very small impact on a train speed

It does, however, impact acceleration time quite severely.

[Iorek]

And yet this is how real life rail networks are designed - in the UK anyway, so there must be something going for them.

sorry, off topic but this made me laugh so hard.

having spend hours on platforms waiting for hour late trains, the "UK rail system" is not something to emulate.
in the "real world" there are other considerations, land ownership, politics, etc.

Perhaps factorio should have Biters charging the player 60,000 copper plate per rail segment in areas of outstanding natural beauty!









Given the size and duration of most Ore patches in this game on default setting, its hard to argue for more than 2 cargo. I find single headers with loops to be simpler when dropping blueprints with multiple patches (esp in bobs mods with multiple ore types).

Single head, single cargo allow for small compact circular mining outposts which are easy to defend and fit most default ore sizes.

I have played a few games with double headers which makes PAX stations simpler and cleaner and you can offload more centrally, but I have also had problems with these types of trains when not using filter inserters.


Its a game, its fun to try new things. Why not simply try various methods.. don't get stuck doing the same thing, enjoy doing something new! I am currently trying double headed trains with 5 cargo wagons simply to see if it works and what happens.... Its horrible trying to defend the massive stations this creates, but its new and fun!

[ssilk]

To throw in a though that came just in the last minute:

I think we can say at this point: 2-headed design has an advantage, if you need to built small. Smaller stations, tighter rails, smaller footprint.
Fully agreed.

The point of my thought is now: Can we say, if you make your train bigger and bigger, that this advantage changes more and more to Loop-based design?

I guess yes and have some reasons. But let's make some definitions first, so that we can discuss about the same things:
A "small layout" is in my opinion a railway-network with less than - hm - 2000 tiles in diameter. More or less. Which means: If your outposts are within 1000 tiles around your main base we may speak from a "small layout". Maybe we can reduce that more to 500 tiles, but I think it is not above 1000.

So - logically - a "big layout" is above that radius of 1000 tiles.

Now I watched this: The smaller the sizes, the narrower everything is, the more advantage is in saving space, saving building time, etc. Advantage for 2-headed trains.

But with growing factory and need for building outposts etc. you reach a point, where this changes and the loop based wins more and more ground. Reasons:

- Loop based enables single headed trains and single headed trains are in general faster (relation between length and transport capacity is lower).
- Loop based design can leave the train-stop in the same direction: The next train can come a lot earlier in.
- More space needs less stops: Loop based design lefts more space for the trains to wait without hindering other trains to drive.
- The tracks are in general longer with loop based design (because of the loops), but with the higher end-speed trains negotiate this disadvantage the longer the tracks are.
- The longer the distances between the stations, the more advantage have faster trains vs. slower.

Ergo: With Loop-based design you can transport faster, when your train network gets bigger.

[Deadly-Bagel]

That's true, I'm yet to see any big bases use two-way trains or at least two-way stations in their big unloading areas because of how long each train ties up the station.

[Avezo]

I didnt' really expect to respond to my own thread, I intended to just listen, but I've actually just recently seen 2-headed station setup with furnaces next to it on multiplayer map (Goodbit's Earth 2 or something) and it was BEATIFUL in its simpliciticity. I'm pretty sure I'm goint to go 2-headed for now until my base gets big enough to change it.

[Hannu]

It's not that Factorio locomotives can't push, they simply have no reverse gear. But you can still stick them at the back, facing forwards, and get power from them.

They have. You can reverse in manual mode. I think that they are just practical choice for gaming. In real life you are not allowed to reverse trains on line if you do not have control car at the end of the train. There are control cars for passenger trains but I have never seen them for freight trains. In some countries they put a locomotive on both ends if freight trains. I think that it should be possible in Factorio too such a way that all locomotives in train would push in spite of what direction they are. But locomotives are so cheap and simple to build that I do not see reason to make separate control cars.

[Hannu]

Two directional trains may have some advantage in small systems with short trains and loops are slightly better in large layouts and long trains. But this is mostly opinion thing. It is possible to get flawless operation with enough capacity by both ways. Costs of railroad network and rolling stock are practically negligible (maybe except some super poor setting) and construction robots build and disassemble both kind of systems with no practical difference.

I like longer trains which looks like real trains in my country. I also like realistic looking railyards (except those loops). Therefore I like to build systems one directional trains and reversing loops mainly for aesthetic reasons.

I use also bidirectional one way tracks for long ore tracks with low traffic even I could build double track as easily with bots. I build side rail for passing after every 300-500 meters. With proper signalling they work perfectly. It is also for aesthetic reasons. I like to travel with my work train between stations and it makes travels more interesting if there are some realistic like happenings, like train passings.

[Boogieman14]

I tend to mix and match loops and 2 headed trains between games but often also within the same game. It all depends on my mood, the style I decided on for the game and various other factors. There's definitely not one single superior solution, it all depends. I might have loops on my high traffic stations, while stations that are only serviced by a single train have the train reverse out of the station. What I do tend to be fairly consistent in lately, is that my main track is three lanes. One up, one down and a center track for my personal shuttle and the FARL train (which, at 5-7 wagons, tends to be extremely slow, so rather not have it mess up the flow on the regular lines)

[mrvn]

I don't really get two-way trains... You need two lanes of track anyway so trains can pass each other and you're saving the 50 or so iron of building a loop but spending 280 on the extra locomotive. To boot, having trains constantly switch direction means no consistency with the carriages' order.

You have a single track but you put the stations on a side track. So basically you go two lanes for the station with one track going straight and the other having the station. Trains can then pass each other at each station but if there is no conflict they can race straight through at full speed. Putting stations on a side track is important for loops too or one train will hold up the whole loop if it is slow to unload.


One thing nobody has mentioned yet though. How about loops with 2-headed trains?

It's easy to make a single lane loop through or around your base and then branch of stations as end terminals wherever you feel like it. Trains will always go in one direction around the loop but reverse when they stop somewhere.

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[Fish]

I tend to mix and match loops and 2 headed trains between games but often also within the same game. It all depends on my mood, the style I decided on for the game and various other factors. There's definitely not one single superior solution, it all depends. I might have loops on my high traffic stations, while stations that are only serviced by a single train have the train reverse out of the station. What I do tend to be fairly consistent in lately, is that my main track is three lanes. One up, one down and a center track for my personal shuttle and the FARL train (which, at 5-7 wagons, tends to be extremely slow, so rather not have it mess up the flow on the regular lines)

How do you ensure the middle track will only be used by your own shuttle and the FARL train?
I'm having some trouble with train pathfinding in my current game.
I'm using loops and a circular track design that goes around my main base so trains have multiple routes to choose from. But that occasionally result in weird path finding behaviour and trains making big detours.

Or do you simply not connect the middle rail to your other rails?

[Boogieman14]

Or do you simply not connect the middle rail to your other rails?

That Obviously there's crossings, but switches are layed out in such a way that a regular train won't be able to get on the service track.

As for your pathfinding issues: an occupied track has a higher cost than a non-occupied track. Multiple trains in one path might add up to a cost that's so high that the big detour is considered cheaper. What you're seeing might be expected behaviour then

[BenSeidel]

I'm using loops and a circular track design that goes around my main base so trains have multiple routes to choose from. But that occasionally result in weird path finding behaviour and trains making big detours.

I always thought that that train pathing was buggy in that way as some of my trains would go through massive detours for no apparent reason. It wasn't until one day when I left a new outpost just before the supply train and saw it choose a strange path much longer than the one I expected it to take (right round the top of my base). But it turns out that the machine is smarter than me as it beat me back to the yard.

[Dasani]

Loop for me, 100% of the time. No question, no doubt.

I run absolutely massive factories and I typically have a single main rail line that I just continue to expand on. There are little branches off here or there where the trains stop to drop or pickup their loads, but the main line has about two dozen trains running on it at full speed at any given time. Using some sort of two-headed train is so impractical and infeasible for a setup like mine on such a large scale, it could just never work. You'd have delays while the line was busy or wasted track to run parallel lines and so on. There's just no point when a loop system takes care of it completely.

It takes a bit more investment initially, and I can see how you might be inclined to be lazy about it and just want to run a single track, especially for your first train if it's just going from A to B, but for a large factory and multiple expansions ferrying in goods from all over the world, you just can't get by with the kind of inefficiency of a two-headed train. You can't have a single track that handles a dozen trains at once efficiently when they have to backtrack both ways over the same rails.

No sir, loop for me. Always. There's not even a question.

[Wackerstamfer]

You can't have a single track that handles a dozen trains at once efficiently when they have to backtrack both ways over the same rails.

No sir, loop for me. Always. There's not even a question.

Thats why I have double headers on a double track. Dead-end stations are just so much easier! And without loops trains always take the same route

[mrvn]

It would be nice if one could say which way a double ended train should reach a station. As is you have to make your trains palindroms, of which trains only carrying one thing are a special case, or make sure every trains has an even number of stops.

[Boogieman14]

You can't have a single track that handles a dozen trains at once efficiently when they have to backtrack both ways over the same rails.

No sir, loop for me. Always. There's not even a question.

You misunderstood the question The 2-headed train option isn't about having a single track to handle all trains. It's essentially about using Terminus stations vs RoRo (Roll on-Roll off) (see http://wiki.openttd.org/Railway_station#Basic_stations for examples). The inbetween network is, with some minor differences, mostly the same. You'd still have two one-directional tracks.

[ssilk]

Hm. Yes. Factorio Community should use the terms RoRo and Terminus instead! Because when I read the topic first I thought:

Loop: A rail-network, that is constructed as loop or circle. Either clockwork-direction or anti-clockwork-direction. One direction only. Makes sense around a lake, for example.

2-headed: A train that has two heads and can drive in both directions. Doesn't say anything about the station he drives through.


I fixed the topic to fit this.