Mixing Transfer and load orders

[erick.thompson]

I have a situation where I need an order combination that I can't figure out. It's a fairly simple problem: I have two stations, one is a loader station at an oil well, and the other is a collector station where the train from the loader station transfers all oil (transfer and leave empty). The way that the system evolved, I now have engineering supplies going to the collector station. What I want is to add an extra wagon for the engineering supplies so that the oil is transferred and the engineering supplies picked up. Then, at the oil well, the engineering supplies are dropped off when the oil is loaded. Is this possible?

Thanks,
Erick

[CaesiumFarmer]

If I understand you correctly, you are adding a wagon to the train carrying oil that will carry engineering supplies back to the oil wells. If you used "transfer and take" orders, you would be dragging oil back to the oil well. To my knowledge, the only way to fix this would be to have a separate station or run another engine instead of just using the oil engines.

Hope this helped.

[erick.thompson]

Is there a transfer and take? I haven't seen that option before.

Thanks,
Erick

[CaesiumFarmer]

When you use the "full load all/any cargo" in combination with "transer" you get "transfer and wait for full load" and "transfer and wait for any full load" respectively.

[FooBar]

That idea only really works with CargoDist or YACD, when the cargo knows where it wants to go. In normal OpenTTD, you'd indeed be hauling back oil without an additional station.

[CaesiumFarmer]

I didn't know what CargoDist was so I looked it up. Cool stuff. Link here for anyone that happens by this thread who doesn't know what it is.

[Eddi]

"transfer and take cargo" only works when you can guarantee that there is a train waiting that picks up the transferred oil immediately. otherwise the train would pick up the oil that it just unloaded. this is why "transfer" automatically uses "no loading" by default, because there are only very rare cases where something different is useful, but you can disable "no loading" manually by choosing "take cargo if available" (you likely won't be using full load for supplies)

on the oil well station you don't need any special modificators. just "full load any" will be fine

[Zuu]

"transfer and take cargo" may also be useful if you have an autorefit order. Eg you drop wood and then refit to goods and then take cargo. This of course works best with the default industries and other industries that doesn't have a (too high) delay in goods generation.

[Lukenwolf]

"transfer and take cargo" only works when you can guarantee that there is a train waiting that picks up the transferred oil immediately. otherwise the train would pick up the oil that it just unloaded.

Which I would consider a bug, rather than a feature I'm currently at work, so I can't look into the source, but I think it should be possible to 'tag' cargo units in a way that a train doesn't load cargo that it has just unloaded.

The oil is of course a rather tricky thing. In subtropical the scenario would be possible, because there the tankers usually are refittable to oil and water, so you would add a refit order to water, preventing the train from picking up the oil it has just dropped off, but that's a solution to a problem that shouldn't be there in the first place.

[FooBar]

Speaking of autorefit, what if one were to autorefit the oil wagons to something else. Then it may just be possible that "transfer and take cargo" doesn't load back the same oil. As long as the engineerings supplies wagon cannot be reffitted to this same "something else", it might just work.

[Eddi]

Which I would consider a bug, rather than a feature I'm currently at work, so I can't look into the source, but I think it should be possible to 'tag' cargo units in a way that a train doesn't load cargo that it has just unloaded.

we have discussed this like a million times already. it just will not work. just imagine three out-of-town airports, with busses transferring to and from the airport, and planes transferring between two airports each.

you will end up with passengers going in circles, because they can board plane A after boarding plane B and C.

things like this cannot ever work without proper destinations.

[Lukenwolf]

I know that, Eddi, but your example misses the point. Was meant to work with different cargo types. A train shall transfer some cargo to some station and pick up some OTHER cargo there.

You have station A, where the train loads oil and unloads engineering supplies, then it shall go to station B with the tankers full and the waggons for supplies empty. At station B it is supposed to unload the oil and load e-supplies and go back to A with the tankers empty. With the current set of orders, this isn't possible, because the train would happily reload the oil it has just unloaded. There are two possible solutions for that:

a) disallow cargo to be loaded to a vehicle that has just unloaded it - or
b) extend the orders system, so that load/unload/transfer orders can be applied with specific cargos, for instance 'transfer (oil) and take cargo (goods)'

[Eddi]

I know that, Eddi, but your example misses the point.

no, i don't. the point was that no dev will accept a known broken feature.

[Lukenwolf]

What broken feature are you talking about?

[FooBar]

The one you're suggesting. It may look good on paper initially, but allow me to illustrate with another example that it doesn't work, even though Eddi already has given one.

Assume two coal mines, one power plant. One station at each, one station in the middle where the coal is first collected from the two mines and then from there with a different train hauled to the power plant. Not even an unrealistic example.

Orders:
Train A
1: Coal mine 1 (full load)
2: Central station (transfer and load)

Train B
1: Coal mine 2 (full load)
2: Central station (transfer and load)

Train C
1: Central station (full load)
2: Power plant

Now chances are train A will load the cargo from train B and vice versa, and that train C will stay empty all the time.

[Lukenwolf]

Now I get it. That would outlaw the 'tagging' solution, but if you could specify cargos in loading and transfer orders, it would work.

[Railwaymodeler]

May I propose a possible solution?

The order window, could have another option on the load and unload dropdowns. "Load Only" and "Unload Only:" These options would have a sub-menu of cargos to tick or untick. This would be helpful for some passenger networks that I build.

For example: I have a passenger terminal in town A, connecting town B and C. I have a train that runs from town A, to town B, and on to Town C.

This train has two express cars - one fitted for milk, the other for goods, a mail car, and a passenger car.

Milk is transfered to the passenger terminal in town A via a small milk train, and goods are transfered to the terminal too. Train leaves town A with all cars loaded.

Train gets to town B. Town B accepts goods and milk in addition to mail and passengers.

Using an "Unload only" option, the train only unloads the milk, passengers and mail. Though the town accepts goods, I want them kept on the train, as town C also accepts goods.

Train proceeds to town C. Milk car is empty. All other cars unloaded and delivered. Town C has goods waiting, but I do not want the train to pick them up, as another train carries them to another town. Load only would be set to milk, mail, and passengers.

Leaving town C, which was not too big, the passenger car is only half full. Back to town B, and the order is set to only unload mail. Passengers waiting can board only, mail loads and unloads.



Would this be workable? This would be very handy for many of my games.

[mfb]

@FooBar: Your example is unrealistic, as the proper order would be "Transfer and leave empty" anyway. If both coal mine pickups have a power plant close to them (and therefore the trains have a reason to pickup coal at the transfer station), it would be useful to load the coal from the other train.

"Only pickup cargo which did not already visit your previous cargo pickup stations" would already help a lot. It would allow "bus line <-> airport <-> airport <-> bus line" and similar designs.
Multiple bus lines would give the risk to transfer the passengers bus->airport->bus without flying, but I do not think this can be avoided easily (as it is similar to the planned airplane transport).

[FooBar]

@FooBar: Your example is unrealistic, as the proper order would be "Transfer and leave empty" anyway.

Please read back where the suggestion came from. The idea was to attach a wagon that would transport engineering supplies in the other direction. With "transfer and leave empty" one cannot load engineering supplies at the central station.

[Pyoro]

If it's been discussed that often before I doubt this is a new idea, but what prevents tagging/flagging/marking/... cargo with its origination instead of its destination? For the airport example, busses could have "Full Load" (at A) then "Transfer and load (except cargo from A)", planes would have "Load (only from A)" (or "Load (except B, C, ...) and obviously similar for airport/bus stations B, C... . If players tried complex transfer combination this might require at some point "except A, B, C, D, E, F...", which doesn't sound too comfortable to use, but it should least work better and less complicated than separate on/off stations and working that out, or not?