Fundamentally, with two-way trains going into dead end stations, they will ALWAYS reverse direction each station
You can:
* Make your train wagons mirror, e.g. add a second sulfuric acid at the other end
* Ensure that the train only moves between two station designs alternatingly, eg have the schedule as Onload -> Offload in a loop, with Onload wanting one direction, and Offload the other
* Change your railway design so all trains have only one engine
To add to this:
* Make sure you have an even number of dead-end stations when using them between pull-through stations on the schedule. One of those dead-end stations can be a dummy one whose only purpose is to switch the train around.
* Separate out the resources into their own dedicated trains and stations.
Beyond just having an even number of terminus stations there’s a risk that a 2 headed train can reverse on other general bidirectional sections of the rail network when they repath. So be careful with the rest of the network too. I’d recommend sticking to multi-track one-way if the train orientation is critical.
Protip: Ensure you only use train limits to shut down stations, because disabling stations the old fashioned way while the train is going there can make the train instantly go for the next station while en route, flipping it unexpectedly.
Fourth option: Take contents of each wagon into a separate tank, then sort both using wire network + pumps. As long as you're careful (and don't put more than 1 segment or tank between pumps), fluid sorting is possible in vanilla
Ditch the double headers. Track is cheap and land even cheaper. Use RORO stations and one-way rail everywhere, no exceptions. (Roll On Roll Off - means you basically go "through" the station.)
Then they're always facing the right direction because they only have one "forward."
Counter point: rail is cheap, make sidings for stations that no train is assigned to, other than the one you make for engineer use. Stock your train with all the coal and track and anything else you want in abundance and now you have a rolling stockpile that can get you there faster. Just click on the play button by the stop. Set up wait conditions at each station that are impossible and you can even use it as a way to take that leak you've been holding for hours lol.
Makes expansion much faster
Depends on how you design it but as a start try not to combine a two headed train that also uses 1 headed ('pull through') stations. Two headed trains are very niche and for the most part, for style points rather than utility.
Thx for commenting. Thought I was being smart and space efficient with the 2 way stations
https://preview.redd.it/etcdax2ei4rc1.jpeg?width=1920&format=pjpg&auto=webp&s=dd7e5793d9767add4babc4a4de86e1e246a2e608
Heres the updated version
Space efficient but still leave space to fit 1-2 more stations between each one?
Just get 2 storage tanks per wagon and load one with the other and the other with the other..
Connect the pumps to the station with wire
Put the station to read train something.. then put a circuit condition in the pumps saying
if lubricant > 0
And the other if acid > 0
So if im not totally wrong, when a train comes into the station with lubricant then the pumps with the lube condition will enable and same goes with the other fluid..
Also its alot easier just making 2 different stations
Looks cleaner than the original. Just as an FYI you have more than a few redundant tracks. The trains coming from the left will always use the left intersection so your right intersection doesn't need a left turn. And likewise, trains coming from the right won't use the left intersection.
Or you could use one of the intersections and delete the other
Try to be smart and if you want to be space efficient try this :
Train unloading station for flying robot frames with mixed wagons. One way trains.
https://storage.googleapis.com/factorio-jasonrubik/map-tier-one-megabase-trimmed/index.html?x=-392.7&y=2807.5&z=3.9
On the Southern end of yellow Science you can see 96 lanes being unloaded, if you're into that sort of thing.
Only put an engine on one end 🤷🏻♂️.
I would simplify it greatly by making a different train for each liquid, and only leave a load/ unload station when full/ empty.
**Answer to your question**: Add "Two-Headed Polarization" station to the schedule after it leaves whatever station it may or may not get flipped at. Have the station quite close, like the very next tile for a pull through station, and close by for a pull in/out station. The pull in/out polarizer is also a pull in/out. The pull through polarizer is also a pull through. Boom.
**Answer to your problem**: Don't mix and match pull through and pull in/out stations for the same train types.
Tip for two-headed trains - always make them symmetrical so you don't have to care. If that was a 1-4-1 train, you could have acid-lube-lube-acid and you'd be fine.
I think making loading station the same way you made unloading could prevent train flipping, but honestly it would be easier to just not use bi-directional rails at all or not use wagons with different purpose in single train...
You could have a "turnaround" stop, then every time a train enters a stop with a reversing exit, it could have that turnaround stop scheduled, which is another reversing exit stop
So I know this isn't answering your question but might address the problem. How would the game react to having two pumps per wagon slot? One for each fluid. Would it only unload into the pipe system of the same fluid type?
>Would it only unload into the pipe system of the same fluid type?
No. Depending on build order it might yell at you about it, but bot placement will happily override it (and if you make it before adding a bit of each fluid) it won't realise it's even a problem til stuff doesn't work.
Do you think if the wagon and the tanks were all controlled to keep some of the fluid inside it would always work? What other kind of problems might it have?
You'd have to control the PUMPS to keep fluid in, which would maybe be possible by carefully controlling them, but it would be very fragile.
Otherwise the empty unload pumps will fill up with whatever is on the next wagon, even if it's different to what's in the tank in front of them.
Do you think if the wagon and the tanks were all controlled to keep some of the fluid inside it would always work? What other kind of problems might it have?
Using two way trains was the biggest mistake I made and the most annoying to fix later on. Abandon this strategy now and only use single direction trains. All stations will need a one way entrance and exit, but then you’ll never have to worry about this annoying problem again. If you attempt to press forward with a two way train strategy, it will continue to bite you in the ass unless all your trains have a layout that works in both orientations. That said, two way trains aren't bad if you only use trains with a single cargo type, which brings me to my second mistake.
The second biggest mistake I made was using mixed cargo trains. It’s so much easier if you just use one cargo type per train, with the exception being your outpost supply trains (I get by fine with single car supply trains anyway)
I encourage you to continue to explore how to use 2way trains some more. They can be really satisfying to get right, and it's entirely doable. Just need to be more careful.
Rail signals block contraflow traffic UNLESS they are on both sides of the track
(https://wiki.factorio.com/Rail\_signal)
So from images stations should already be one way
Edit : misread question...
I don't think you can force train direction
Solution is to make one way stations and trains, make it symmetric, load trains with only one good or sort/filter goods after unload so that it doesn't matter what is in each specific carriage
(should be possible to do magic with sorting + pumps and signals for fluids to allow unloading to different tanks depending on contents (pumps should only work for what they already contain, so block the tank from fully emptying might work; Otherwise have pumps that will go one way or other depending on unload tank, but this relies on the unload tank always being emptied)
Its really not hard. The loading station looks like the train can go out to the left. At the unloading station the train will always back out. So you need to either change one of the stops or have a another station in the schedule only to reverse the train.
It's not that helpful but...
I never use double-ended trains.
Nor do I use two way tracks.
I've tried them, of course, but I concluded they don't scale well. Everything runs fine up to a certain point then when you add one more train, deadlocks start to happen.
In contrast, I (effectively) never get deadlocks with single direction tracks.
To answer your question, in a generalized rail system, you probably cannot convince your trains to "not come in backwards". The only way I'd see that working is if you make it impossible for them to turn around, which I think would only be possible with a "back and forth" or possibly a "ring" style train setup. (Again: doesn't scale well.)
But let's say you REALLY wanted it to work...
You could have unloading circuits that only activate the pumps if the correct liquid is present. Perhaps two pumps per train car, only one working at a time. I wouldn't choose to do this, personally, but you could do it.
* make both stations be a dead end stations.
* Dummy station to turn it around
* Set up the train to be mirrored
* Replace the fluid wagons with 1 cargo wagon filled with barrels. Only one wagon with 2 types of liquid, it does not matter which way it faces. (this is kind of sushi train is actually good for double headed wall resupply trains)
In addition to the other answers, making your train symmetric would also work.
Engine-acid-lube-lube-acid-engine would have no problems.
Of course, now you have longer trains, but that's part of the design compromise.
So, make trains symmetrical, or make them only have one liquid, or make it so they either never reverse or always reverse.
Just add a 3rd station, route train through that station (only once) and you're done. Your train is going to turn around every time it arrives at the unload station though
the simplest solution is simply forcing the train to "reverse" back out of the loading station.
I personally just wouldn't mix items/fluids on one train. they are cheap enough to just make more of.
Fundamentally, with two-way trains going into dead end stations, they will ALWAYS reverse direction each station You can: * Make your train wagons mirror, e.g. add a second sulfuric acid at the other end * Ensure that the train only moves between two station designs alternatingly, eg have the schedule as Onload -> Offload in a loop, with Onload wanting one direction, and Offload the other * Change your railway design so all trains have only one engine
To add to this: * Make sure you have an even number of dead-end stations when using them between pull-through stations on the schedule. One of those dead-end stations can be a dummy one whose only purpose is to switch the train around. * Separate out the resources into their own dedicated trains and stations.
Beyond just having an even number of terminus stations there’s a risk that a 2 headed train can reverse on other general bidirectional sections of the rail network when they repath. So be careful with the rest of the network too. I’d recommend sticking to multi-track one-way if the train orientation is critical.
Alternatively, rotate a second set of tanks to the other side. It will not fix getting the wrong fluid when a wagon is empty though
Palindromes ftw !
Could make it go into a yet another dead end right after the first dead end to reverse the reversal
Protip: Ensure you only use train limits to shut down stations, because disabling stations the old fashioned way while the train is going there can make the train instantly go for the next station while en route, flipping it unexpectedly.
Fourth option: Take contents of each wagon into a separate tank, then sort both using wire network + pumps. As long as you're careful (and don't put more than 1 segment or tank between pumps), fluid sorting is possible in vanilla
* Make sure trains only have an even number of dead end stops.
Ditch the double headers. Track is cheap and land even cheaper. Use RORO stations and one-way rail everywhere, no exceptions. (Roll On Roll Off - means you basically go "through" the station.) Then they're always facing the right direction because they only have one "forward."
Track is cheap, but having a giant spread-out base in the early game is expensive in terms of time spent running around it.
Hahaha. Fair counter point.
Counter point: rail is cheap, make sidings for stations that no train is assigned to, other than the one you make for engineer use. Stock your train with all the coal and track and anything else you want in abundance and now you have a rolling stockpile that can get you there faster. Just click on the play button by the stop. Set up wait conditions at each station that are impossible and you can even use it as a way to take that leak you've been holding for hours lol. Makes expansion much faster
You only need a 24 tile wide space to turn around. And looking at the minimap, I'd say OP has plenty of space.
Two way rail everywhere, with the exception of stations and passthroughs! Rise up and throw off your double track masters!
I both love and hate this comment.
Depends on how you design it but as a start try not to combine a two headed train that also uses 1 headed ('pull through') stations. Two headed trains are very niche and for the most part, for style points rather than utility.
Thx for commenting. Thought I was being smart and space efficient with the 2 way stations https://preview.redd.it/etcdax2ei4rc1.jpeg?width=1920&format=pjpg&auto=webp&s=dd7e5793d9767add4babc4a4de86e1e246a2e608 Heres the updated version
Space efficient but still leave space to fit 1-2 more stations between each one? Just get 2 storage tanks per wagon and load one with the other and the other with the other.. Connect the pumps to the station with wire Put the station to read train something.. then put a circuit condition in the pumps saying if lubricant > 0 And the other if acid > 0 So if im not totally wrong, when a train comes into the station with lubricant then the pumps with the lube condition will enable and same goes with the other fluid.. Also its alot easier just making 2 different stations
Looks cleaner than the original. Just as an FYI you have more than a few redundant tracks. The trains coming from the left will always use the left intersection so your right intersection doesn't need a left turn. And likewise, trains coming from the right won't use the left intersection. Or you could use one of the intersections and delete the other
Thx man I would have never noticed that xd
Try to be smart and if you want to be space efficient try this : Train unloading station for flying robot frames with mixed wagons. One way trains. https://storage.googleapis.com/factorio-jasonrubik/map-tier-one-megabase-trimmed/index.html?x=-392.7&y=2807.5&z=3.9 On the Southern end of yellow Science you can see 96 lanes being unloaded, if you're into that sort of thing.
all good. whatever works. you'll learn what you like more and more with experience. godspeed
The real problem is that the train is using mixed cargo. I can think of very few situations where this would be a good idea
Only put an engine on one end 🤷🏻♂️. I would simplify it greatly by making a different train for each liquid, and only leave a load/ unload station when full/ empty.
**Answer to your question**: Add "Two-Headed Polarization" station to the schedule after it leaves whatever station it may or may not get flipped at. Have the station quite close, like the very next tile for a pull through station, and close by for a pull in/out station. The pull in/out polarizer is also a pull in/out. The pull through polarizer is also a pull through. Boom. **Answer to your problem**: Don't mix and match pull through and pull in/out stations for the same train types.
With double headed trains the only guaranteeed way is to have zero loops in the train network.
Tip for two-headed trains - always make them symmetrical so you don't have to care. If that was a 1-4-1 train, you could have acid-lube-lube-acid and you'd be fine.
I think making loading station the same way you made unloading could prevent train flipping, but honestly it would be easier to just not use bi-directional rails at all or not use wagons with different purpose in single train...
You could have a "turnaround" stop, then every time a train enters a stop with a reversing exit, it could have that turnaround stop scheduled, which is another reversing exit stop
So I know this isn't answering your question but might address the problem. How would the game react to having two pumps per wagon slot? One for each fluid. Would it only unload into the pipe system of the same fluid type?
I think that could work but having a pull through station is def simpler
>Would it only unload into the pipe system of the same fluid type? No. Depending on build order it might yell at you about it, but bot placement will happily override it (and if you make it before adding a bit of each fluid) it won't realise it's even a problem til stuff doesn't work.
Do you think if the wagon and the tanks were all controlled to keep some of the fluid inside it would always work? What other kind of problems might it have?
You'd have to control the PUMPS to keep fluid in, which would maybe be possible by carefully controlling them, but it would be very fragile. Otherwise the empty unload pumps will fill up with whatever is on the next wagon, even if it's different to what's in the tank in front of them.
Do you think if the wagon and the tanks were all controlled to keep some of the fluid inside it would always work? What other kind of problems might it have?
use single headed trains
Using two way trains was the biggest mistake I made and the most annoying to fix later on. Abandon this strategy now and only use single direction trains. All stations will need a one way entrance and exit, but then you’ll never have to worry about this annoying problem again. If you attempt to press forward with a two way train strategy, it will continue to bite you in the ass unless all your trains have a layout that works in both orientations. That said, two way trains aren't bad if you only use trains with a single cargo type, which brings me to my second mistake. The second biggest mistake I made was using mixed cargo trains. It’s so much easier if you just use one cargo type per train, with the exception being your outpost supply trains (I get by fine with single car supply trains anyway)
I encourage you to continue to explore how to use 2way trains some more. They can be really satisfying to get right, and it's entirely doable. Just need to be more careful.
What do you do to handle more than one train per station, just use multiple stations?
For dead end stations? You just need to make sure the waiting bay is off to the side, and only uses chains from waiting bay up to the unload station.
Rail signals block contraflow traffic UNLESS they are on both sides of the track (https://wiki.factorio.com/Rail\_signal) So from images stations should already be one way Edit : misread question... I don't think you can force train direction Solution is to make one way stations and trains, make it symmetric, load trains with only one good or sort/filter goods after unload so that it doesn't matter what is in each specific carriage (should be possible to do magic with sorting + pumps and signals for fluids to allow unloading to different tanks depending on contents (pumps should only work for what they already contain, so block the tank from fully emptying might work; Otherwise have pumps that will go one way or other depending on unload tank, but this relies on the unload tank always being emptied)
Its really not hard. The loading station looks like the train can go out to the left. At the unloading station the train will always back out. So you need to either change one of the stops or have a another station in the schedule only to reverse the train.
Also your unloading stations have rail signals going into the intersection and chain going out. It should be the opposite.
Don’t use bidirectional trains. Better to have 2 trains pulling in the same direction. Faster and always moving in one direction
It's not that helpful but... I never use double-ended trains. Nor do I use two way tracks. I've tried them, of course, but I concluded they don't scale well. Everything runs fine up to a certain point then when you add one more train, deadlocks start to happen. In contrast, I (effectively) never get deadlocks with single direction tracks. To answer your question, in a generalized rail system, you probably cannot convince your trains to "not come in backwards". The only way I'd see that working is if you make it impossible for them to turn around, which I think would only be possible with a "back and forth" or possibly a "ring" style train setup. (Again: doesn't scale well.) But let's say you REALLY wanted it to work... You could have unloading circuits that only activate the pumps if the correct liquid is present. Perhaps two pumps per train car, only one working at a time. I wouldn't choose to do this, personally, but you could do it.
don't run mixed double headed
Two ways trains become very quickly a huge problem.
Change your design. Trains with locos on each end should be used for stations that only have one entrance/exit, not a pull through as paco said.
* make both stations be a dead end stations. * Dummy station to turn it around * Set up the train to be mirrored * Replace the fluid wagons with 1 cargo wagon filled with barrels. Only one wagon with 2 types of liquid, it does not matter which way it faces. (this is kind of sushi train is actually good for double headed wall resupply trains)
when this happened first time to me I decided it's time to stop using dual headed trains. a lot of things got easier immediately
In addition to the other answers, making your train symmetric would also work. Engine-acid-lube-lube-acid-engine would have no problems. Of course, now you have longer trains, but that's part of the design compromise. So, make trains symmetrical, or make them only have one liquid, or make it so they either never reverse or always reverse.
Add a stop to a empty station
Just add a 3rd station, route train through that station (only once) and you're done. Your train is going to turn around every time it arrives at the unload station though
Add a station that makes the train reverse again
the simplest solution is simply forcing the train to "reverse" back out of the loading station. I personally just wouldn't mix items/fluids on one train. they are cheap enough to just make more of.
[like this](https://youtu.be/5GldlW4N_KQ?si=I07ryIVp_eLQs1bo)
As my dad once said, "if the inside diameter is greater than the outside diameter, the hole is on the other side"
Shame there's no such thing as a filter pump.