Locomotives to provide driving power in both directions

[joeykins]

TL;DR

Locomotives should work more like real life: they should still be directional in terms of interpreting signals, but a "backwards" facing locomotive should still be able to provide drive power for the train.

What ?

Right now a 1-4-1 config train only ever uses 1 of its locomotives to provide driving power, with the other being dead weight and making the overall train slower. This is somewhat counter-intuitive and doesn't reflect how trains work in the real world. The automated locomotive acting as "driver" should still need to be facing the right way in order to interpret signals and to ensure predictability, but a backwards-facing locomotive should still use its engine to provide driving force for the train in order to improve acceleration.

Why ?

More efficient trains make everyone happy!

[Tertius]

While it's a valid request for Factorio, it's not always been the case that locomotives in the real world are bidirectional. If you ask chatgpt for details about that, you learn that steam locomotives are unidirectional with a few exceptions for special demand such as shunting locomotives or for rails with many curves, but not for the widespread general use. Diesel locomotives have more bidirectional designs, but many of them still have unidirectional designs. Electric locomotives are usually designed for bidirectional operation.
Rule of thumb: the more recent the locomotive design, the more bidirectional they become.

However, the general locomotive design in Factorio seems to be the steam locomotive. Even if it's able to burn nuclear fuel, it's modeled after the steam locomotive, and these designs are usually unidirectional for general route service.

In my opinion, it should stay this way. It adds depth to the game, because you pay for a more simple track design with the dead weight, and you have to balance between track design and train speed/train behavior. With bidirectional locomotives bidirectional tracks come with no downside, and that feels not balanced in comparison to unidirectional 2 track designs.

[SoShootMe]

While it's a valid request for Factorio, it's not always been the case that locomotives in the real world are bidirectional. If you ask chatgpt for details about that, you learn that steam locomotives are unidirectional with a few exceptions for special demand such as shunting locomotives or for rails with many curves, but not for the widespread general use.

I think it's safe to say that learning from ChatGPT is at best ill-advised . AFAIK it is, and always has been, the case that locomotives are physically able to go just as fast in either direction, including steam locomotives. Other considerations may limit fast running in reverse, most obviously visibility for the driver.

In the UK at least, it was quite normal for steam locomotives to run backwards on branch lines, connecting the front end of the locomotive to rest of the train. This requires only a fairly simple "run-round" loop at the ends of the line.

Also in the UK and in mainland Europe (perhaps also elsewhere), many high speed passenger services have had "top and tail" locomotives each providing power since the 1970s. These seem to be disappearing or have disappeared, replaced with multiple units that have driven wheels distributed along the train. In the UK, IC225 (designed for 225km/h top service speed) trainsets run/ran with class 91 locomotives at one end and an unpowered driving van trailer (DVT) providing controls at the opposite end of the train to the locomotive, so the locomotive pulls the train in one direction and pushes it in the other.

All diesel/-electric and electric locomotives I can think of with a freight role in the UK have cabs at both ends (this is also true for locomotives I've seen in mainland Europe), and usually run with a locomotive only at the front, although I have occasionally seen "top and tail" freight trains where the trailing locomotive is dead weight.

But realism isn't everything in Factorio and I agree with this:

In my opinion, it should stay this way. It adds depth to the game, because you pay for a more simple track design with the dead weight, and you have to balance between track design and train speed/train behavior.

[Kyralessa]

I think it's safe to say that learning from ChatGPT is at best ill-advised .

One could say the same about randos from the internet.

[mmmPI]

I think it's safe to say that learning from ChatGPT is at best ill-advised .

One could say the same about randos from the internet.

I'm a random person from the internet, and sometimes i use perplexity.ai , because it can gives sources for the answer, when asked about trains it gave an aswer using "8 sources" https://www.perplexity.ai/search/explai ... uLKxygYg#0

When you look closely the "source number 7" is funnily enough, from the factorio forum, this post : viewtopic.php?t=59429. I just wanted to point out the circularity which is only visible when the AI gives sources

Also there exist mod for this : https://mods.factorio.com/mod/MultipleUnitTrainControl

[georgejohn12]

The suggestion to allow locomotives in Factorio to provide driving power in both directions, regardless of their orientation, would make train mechanics more realistic and efficient. In real-world trains, multiple locomotives in a consist contribute to the train's propulsion, even if some are facing "backwards." Implementing this in the game would enhance the performance of configurations like 1-4-1 by allowing both locomotives to contribute to acceleration and overall speed, reducing the inefficiency of one locomotive being dead weight. While the front-facing locomotive would still interpret signals to maintain predictability and control, the ability of a backwards-facing locomotive to provide power would align better with how actual trains operate and make train setups in Factorio more effective and satisfying for players.

[robot256]

I made my mod Multiple Unit Train Control to counteract the reversing penalty. With so many other things in Factorio deliberately made so players can complete the game in a seamless and efficient manner, I don't see the value in adding arbitrary penalties to bidirectional trains.

Bidirectional trains are easy for quick and low-capacity lines, just like in real life. But they they don't scale up quite as easily as one-way trains, they are harder to signal for complex junctions, and at a certain point you have to run them mostly on one-way rails anyways for throughput. I think thise penalties are enough to keep the game interesting.