Advanced train length and fuel considerations, and long-train high throughput intersection

[zOldBulldog]

I like one-direction trains. Throughout my Factorio playing I used 1-2 trains and been very happy with them. I probably will continue using them for ore trains on isolated short dedicated routes to minimize the mine station footprint.

But I am considering larger trains for the rest of my cargo and I received an intriguing suggestion. One person suggested using 1-4-1 or 2-8-2 with the locomotives pointed in the same direction. Another suggested going for 2-4-2 or 4-8-4 (also pointed in the same direction).

I have to chose and design my rail blueprints accordingly. Obviously, if space is no issue (like when you reach the megabase stage) it is easy to choose the 4-8-4 and just build big. But when space-cramped (like in the early game) the added performance of more locomotives needs to justify the increased size of stations and intersections, and I couldn't find any information by googling.

1) Could someone please give me an idea of "how much improvement" there is to the overall rail network by doubling the locomotives from 1-4-1 (or 2-8-2) to 2-4-2 (or 4-8-4)?

2) I normally use solid fuel for my trains. I am debating whether to go to rocket or nuclear fuel but the smaller stack size troubles me. Is the longer burn time of these fuels long enough to compensate for their smaller stack sizes - as far as total range is concerned? (My guts say yes, but confirmation from experience would be nice)

3) I need to find a compact but high throughput intersection for these trains. If 4-8-4 (same direction locos) proves to be justifiable, then for that size train (16 long total). Otherwise one for 2-8-2 (same direction locos, 12 long total). Can you recommend one or perhaps even provide a blueprint? (Left hand drive would be ideal, but I'll convert any Right hand drive one if needed)

Many thanks in advance. This matter has had me going in circles for over a day and quite frustrated. (On the other hand, I ended up doing On Track like a Pro while thinking about the matter and I'm now down to just 2 achievements, so that was a win anyway).

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BTW, if you read my other thread in the General Discussion forum and you are wondering why make a separate one here in Help... it is to cover this very specific issue. The other thread is more of a "larger perspective" discussion and I fear it scared away some that could easily answer these specific questions, although it was very useful as the source of these front and back locomotives pointing in the same direction configuration.

[Mr. Tact]

I think it is more of a personal preference thing. Personally, I like 2-4 for ore, 1-2 for oil, and 1-3 for uranium (one car with 50/50 assigned slots for full and empty sulfuric acid barrels). *shrug*

[zOldBulldog]

I think it is more of a personal preference thing. Personally, I like 2-4 for ore, 1-2 for oil, and 1-3 for uranium (one car with 50/50 assigned slots for full and empty sulfuric acid barrels). *shrug*

I am trying to choose my "preference" based on actual technical performance. And more the performance of the network under heavy load than just the simple acceleration of a single locomotive. That is why I asked.

I already know that I prefer trains with 2, 4 or 8 wagons (as it makes balancing unloaded belts easier), but how they perform would tell me the locomotive to wagon ratio I want.

For example, I already know that a 1-4 or 2-8 (1/4 ratio) would cause issues with intersection throughput because they are too sluggish. So I was already planning on a 1/2 ratio for 4 or 8 wagon trains like the one I have in 1-2 trains. Then an experienced railroad player suggested using a 1/1 ratio.

The way I see it is that if in the game play before the Megabase stage I use the same design (scaled up) intersection and a 1/1 ratio gives me only a 20% throughput improvement over a 1/2 ratio then it is probably not worth the extra space it uses, but if it gives me a 50% or more throughput improvement then it is totally worth it. And of course in the Megabase stage space is abundant and so the 1/1 ratio is the obvious choice. But right now I am trying to design for that trickier earlier stage.

[zOldBulldog]

I think it is more of a personal preference thing. Personally, I like 2-4 for ore, 1-2 for oil, and 1-3 for uranium (one car with 50/50 assigned slots for full and empty sulfuric acid barrels). *shrug*

I am trying to choose my "preference" based on actual technical performance. And more the performance of the network under heavy load than just the simple acceleration of a single train. That is why I asked.

I already know that I prefer trains with 2, 4 or 8 wagons (as it makes balancing unloaded belts easier), but how they perform would tell me the locomotive to wagon ratio I want.

For example, I already know that a 1-4 or 2-8 (1/4 ratio) would cause issues with intersection throughput because they are too sluggish. So I was already planning on a 1/2 ratio for 4 or 8 wagon trains like the ratio of 1-2 trains. Then an experienced railroad player suggested using a 1/1 ratio.

The way I see it is that if in the game play before the Megabase stage I use the same design (scaled up) intersection and a 1/1 ratio gives me only a 20% throughput improvement over a 1/2 ratio then it is probably not worth the extra space it uses, but if it gives me a 50% or more throughput improvement then it is totally worth it. And of course in the Megabase stage space is abundant making the 1/1 ratio the obvious choice for that stage. But right now I am trying to design for that trickier earlier stage.

[Lav]

IIRC the optimal speed/acceleration are achieved at 1:2 ratio between locos and wagons. So it's 1-2, or 2-4, etc.

Personally I perfer to use 2-4 trains, and when I need something really big, I build a 2-4-2-4. This makes station expansion really easy. Also you can still send a small 2-4 train to a 2-4-2-4 station and it will unload without issues, and you can send a 2-4-2-4 train to an old 2-4 station and the first half of the train will unload. It's even possible to fully unload a 2-4-2-4 train on a 2-4 station, you just need to extend the rail further and place a second station down the line to allow for the rear 4 wagons to unload (the positioning matches for chained 2-4 trains, but not for 1-2 or 3-6 trains).

[zOldBulldog]

IIRC the optimal speed/acceleration are achieved at 1:2 ratio between locos and wagons. So it's 1-2, or 2-4, etc.

Personally I perfer to use 2-4 trains, and when I need something really big, I build a 2-4-2-4. This makes station expansion really easy. Also you can still send a small 2-4 train to a 2-4-2-4 station and it will unload without issues, and you can send a 2-4-2-4 train to an old 2-4 station and the first half of the train will unload. It's even possible to fully unload a 2-4-2-4 train on a 2-4 station, you just need to extend the rail further and place a second station down the line to allow for the rear 4 wagons to unload (the positioning matches for chained 2-4 trains, but not for 1-2 or 3-6 trains).

To make sure I understood you correctly, are you saying that a 4-4 has no speed/acceleration advantage over a 2-4?

I hope that is what you said, because I was willing to run 4-4 and 8-8n but I really didn't like it. I would much rather use a 2-4 if there is little or no difference in performance.

Also, very cool idea of running the 2-4-2-4 configuration. I have no idea why they do it IRL but I would swear I've seen some real life very long trains with extra locos in the middle. I suspect it might have something to do with better behavior on curves.

[Zavian]

Also, very cool idea of running the 2-4-2-4 configuration. I have no idea why they do it IRL but I would swear I've seen some real life very long trains with extra locos in the middle. I suspect it might have something to do with better behavior on curves.

It reduces the load on the coupling for long trains compared to having all the engines first, then all the cars.