Factorio Forums

Awesome mod, many thanks for making it! I'm at late-midgame tech on a playthrough with a moderate quantity of QoL mods but nothing that changes gameplay the likes of AngelBob or similar. I've unlocked capacity to embark on both purple and yellow science but have yet to design either's production. I'm currently running a small fleet of vanilla-scheduled L-CCC trains to get this far, and now that I've gotten my logistics mall and first-pass uranium processing humming along, I've decided it's finally time to dive into learning how to use LTN for dynamic dispatching.

My post here is a general check-in type of questions. I do not intend to burden the mod author personally and would gladly hope for input from other users as appropriate.

I've set aside a cleared section of land outside of my starter base to plop down some LTN-station blueprints I've downloaded, mostly so that I can examine their wiring and combinator settings. I have a small starter LTN-Depot setup and (I think) that Depot is fully wired and functional, connected to my rail network. Most of it is empty, but some trains remain parked there in unfueled state from having used them as placeholders to visualize lengths of rail needed and designing the fuel-stop. (I was also manually crafting trains at the time, which is what made me take a step sideways to go finally establish my logistics and build-everything malls.)

My test-blueprints are disconnected from my rail network and also disconnected from my signal-wire network.

I'm receiving a low-volume series of console error messages that read, "[LTN] No train to transport items found in depots. Skipping item processing." A parallel message separately indicates a lack of any fluid-tanker trains, as well. I've performed a word-for-word read-through on more than one forum post discussing binary notation, in both the context of LTN NetworkID as well as that of train composition (in other words, I have read the manual, and I have not simply glanced at / skimmed some of the other stuff.) I understand, in principle, that we're discussing 2^n notation. However, I know my study habits and my strengths / weaknesses in learning new skills. I have not found any write-ups or video explanations that specifically connect the meta-discussion of theoretical properties on the one hand with in-game usage examples on the other hand, which is what I'd need to fully achieve my own accelerated breakthrough. If none of those exist, is my only remaining option to simply tinker with the mod and simply address problems as I encounter them? (I'm assuming this last item is "yes.")

My questions: 1.) Given the above, and also given that I have not yet experimented with combinator-defined NetworkIDs, am I to understand that physical separation into multiple rail networks would be a poor-man's "dumb-logic" separation of LTN networks? In other words, if I ran entirely separate rail networks for different cargo-types, can I rely on that to assure that only physically-possible combinations will be attempted for certain Depot-Provider-Requester sequences? With the parallel error messages distinguishing between inserter-freight and fluid tankers, am I to understand that it is possible to run those fleets without necessarily mapping them to separate NetworkIDs?

2.) I have no intention to run mixed-load or less-than-trainload freights outside of certain vanilla-scheduled runs with filtered-slot wagons (outpost resupply, artillery patrols, etc.) but I also do recognize that certain lategame freights (LDS, rocket fuel, etc.) might benefit from having some access to shorter-length trains. Before fully embracing NetworkID flags, what kinds of things can I benefit from at my current in-game stage of base development? For example, I envision running a specific set of train form-factors (L-C, L-CC, L-CCC, and maybe L-CCCC.) I absolutely will not mix wagon-types on a single train; does this mean that I'll actually have 8 train-types when considering L-T, L-TT, etc.? Is my best bet to design separately-named Depots for each of the four [eight] train types?

Thanks in advance, and again, this mod is brilliant. Thank you for this!

Add-on question: Would LTN play nicely with the Train Coupler mod?

Quite the essay. Let's see if i can pick it apart and answer the questions if i find them.

MisterFister wrote: Sun Dec 23, 2018 7:55 pm 1.) Given the above, and also given that I have not yet experimented with combinator-defined NetworkIDs, am I to understand that physical separation into multiple rail networks would be a poor-man's "dumb-logic" separation of LTN networks? In other words, if I ran entirely separate rail networks for different cargo-types, can I rely on that to assure that only physically-possible combinations will be attempted for certain Depot-Provider-Requester sequences? With the parallel error messages distinguishing between inserter-freight and fluid tankers, am I to understand that it is possible to run those fleets without necessarily mapping them to separate NetworkIDs?

Factorio does not expose train pathfinder, there's no way of knowing if a train can possibly path between stops.
If networks have no physical connection NetworkID has to be used to tell LTN trains can't path between them. In this case all stops in every network have to be set to an ID.

NetworkID can also be used to optimize train usage. For example a base stretching mines west to east with a smelter in the middle. Having a depot west and mines west on ID 2 and a depot east and mines on ID 4 while the smelters have ID 6 will prevent trains going from west depot to pick up east mine ore.

LTN distinguishes between items and fluids setting those to different NetworkIDs is not required. It does however make output from LTN Content Reader a bit cleaner.

MisterFister wrote: Sun Dec 23, 2018 7:55 pm 2.) I have no intention to run mixed-load or less-than-trainload freights outside of certain vanilla-scheduled runs with filtered-slot wagons (outpost resupply, artillery patrols, etc.) but I also do recognize that certain lategame freights (LDS, rocket fuel, etc.) might benefit from having some access to shorter-length trains. Before fully embracing NetworkID flags, what kinds of things can I benefit from at my current in-game stage of base development? For example, I envision running a specific set of train form-factors (L-C, L-CC, L-CCC, and maybe L-CCCC.) I absolutely will not mix wagon-types on a single train; does this mean that I'll actually have 8 train-types when considering L-T, L-TT, etc.? Is my best bet to design separately-named Depots for each of the four [eight] train types?

Rocket parts have ridiculous small stack size, large trains prevent a lot of train congestion here. Items that don't profit from bigger trains are expensive intermediates with high stack size and low usage like processing units.

Optimal train lengths vary depending on how much should be sitting in station buffers and network throughput. Generally longer trains are better than more small ones. 2 LCC trains use more cpu than 1 LL-CCCC train while simultaneously clog the network more.
I use the modded equivalent of base 4L-9C and 4L-9T trains for everything in my 2kspm base with a hand full of L-2C for small volume freight like radar or solar panels to rocket silo. Unless multiple depots like east and west are desired to keep paths short this doesn't need NetworkID.

A different approach is to use massive trains exclusively for hauling ores and medium sized trains with better acceleration for shipping intermediate products. This would require either NetworkID or train size limitation.


Having dedicated depots per train configuration is space efficient, but not required. Creating stations capable of servicing different train sizes is possible using Train Composition signals.

MisterFister wrote: Sun Dec 23, 2018 8:00 pm Add-on question: Would LTN play nicely with the Train Coupler mod?

No.
1) LTN requires train composition to remain unchanged for the duration of a delivery and is therefore incompatible with any mod coupling or decoupling trains automatically.
2) LTN requires a complete train in the depot to find the optimal train capacity. Supporting just locomotives at the depot and wagons waiting at provider is way to messy to implement and also wouldn't be optimal utilization of rolling stock.


I hope that answers your questions.

Optera wrote: Sun Dec 23, 2018 9:09 pm Quite the essay. Let's see if i can pick it apart and answer the questions if i find them.

Welp, prior to posting here, I'd just re-read your stickies on unhelpfully brief questions from those who refuse to read documentation. I was merely erring on the side of respectfully verbose, particularly considering my non-technical background.

Optera wrote: Sun Dec 23, 2018 9:09 pm LTN distinguishes between items and fluids setting those to different NetworkIDs is not required. It does however make output from LTN Content Reader a bit cleaner.

Thank you for this, as it validates my own suspicion that LTN Content Reader was worth effort to learn but not necessarily a gateway to using LTN without it.

Optera wrote: Sun Dec 23, 2018 9:09 pm Rocket parts have ridiculous small stack size (...)

Heh. It's been a while since I've played lategame, and I suppose that shows here.

Optera wrote: Sun Dec 23, 2018 9:09 pm I use the modded equivalent of base 4L-9C and 4L-9T trains (...)

Any mods outside of those you've posted under your name on the portal? I ask because I've downloaded most of your other mods and look forward to experimenting with optimizations as to loco-type. In particular, I anticipate at some point searching for some posts as to those mods for inspiration.

Optera wrote: Sun Dec 23, 2018 9:09 pm Having dedicated depots per train configuration is space efficient, but not required. Creating stations capable of servicing different train sizes is possible using Train Composition signals.

Are you using the term "stations" here interchangeably with Depots? I.e., are Depots simply the third category of "stations" overall? (Absent this comment, my instinct would be to reserve "station" for P's and R's, since it's at Depots that I anticipate incorporating fleet-wide fueling as well as residual-offload trash schedules (residual offloading at Depots might be relegated to a vanilla-schedule, I'm not sure at this point.)

Optera wrote: Sun Dec 23, 2018 9:09 pm 1) LTN requires train composition to remain unchanged for the duration of a delivery and is therefore incompatible with any mod coupling or decoupling trains automatically.

Again, I ask about terminology: is the return-to-depot leg of a dispatch encompassed by "duration of delivery"? (I'm assuming yes, as I saw in my search your other post about events firing on train-composition changes.) And regardless, with respect to the default wait-at-Depot scheduling, would it be possible to change a global-default to instruct a train to return to Depot by way of depositing its rolling stock elsewhere and then returning as loco-only to Depot instead of a straight-return?

Optera wrote: Sun Dec 23, 2018 9:09 pm 2) LTN requires a complete train in the depot to find the optimal train capacity.

Even if I pre-empt the mod's attempts to do this with judicious use of threshhold variables to force full-trainload dispatches across the board? (Am I failing to anticipate usage scenarios where full-trainload forcing is more difficult than it seems?)

Optera wrote: Sun Dec 23, 2018 9:09 pm (...) and also wouldn't be optimal utilization of rolling stock.

My personal background is in logistics and fleet management, on both the equipment and personnel sides. I imagine a possibly-interesting edge case that utilizes stationary wagons as wide-form passthrough chests at certain assembly lines. Unrelated to that, I have a fantasy of being able to use decoupling of rolling stock as a method of preserving slot-filters, initially of use to otherwise vanilla outpost supply trains but possibly opening up the later ability for me to reduce my OCD-inspired emphasis on trainload-only usage.

Optera wrote: Sun Dec 23, 2018 9:09 pm I hope that answers your questions.

I am honored by your quite timely and very thoughtful reply. If you ever wanna run some MP, please don't hesitate to think of me.

MisterFister wrote: Sun Dec 23, 2018 10:37 pm Any mods outside of those you've posted under your name on the portal? I ask because I've downloaded most of your other mods and look forward to experimenting with optimizations as to loco-type. In particular, I anticipate at some point searching for some posts as to those mods for inspiration.

I didn't want to promote Train & Fuel Overhaul, it's a mod I made mostly for myself. It changes fuel and train properties to have noticeable progression and differences between different locomotives and wagons, but those massive changes make progression really wonky when used alongside other mods adding or changing trains like e.g. boblogistics.

MisterFister wrote: Sun Dec 23, 2018 10:37 pm Are you using the term "stations" here interchangeably with Depots? I.e., are Depots simply the third category of "stations" overall? (Absent this comment, my instinct would be to reserve "station" for P's and R's, since it's at Depots that I anticipate incorporating fleet-wide fueling as well as residual-offload trash schedules (residual offloading at Depots might be relegated to a vanilla-schedule, I'm not sure at this point.)

To me a station is the infrastructure required to un-/load trains like train stop, control circuits, inserters, buffer chest, asf. Depot, Provider, Requester are specific types of stations.
A provider for fuel items will need control logic similar to depots to only load its fuel into wagons and not locomotives.

MisterFister wrote: Sun Dec 23, 2018 10:37 pm I ask about terminology: is the return-to-depot leg of a dispatch encompassed by "duration of delivery"?

No, but there is an option "Delivery completes at requester" to reset schedules at requester instead of depots. I've added this so trains waiting in stacker depots don't have their already completed delivery still showing. It just makes checking which trains are on delivery in train overview easier. It's deactivated by default since it makes it impossible to tell from where a train with residue came.

MisterFister wrote: Sun Dec 23, 2018 10:37 pm Even if I pre-empt the mod's attempts to do this with judicious use of threshhold variables to force full-trainload dispatches across the board? (Am I failing to anticipate usage scenarios where full-trainload forcing is more difficult than it seems?)

Setting provide and request thresholds to max train capacity or higher will result in always full trains.