Invisible loco

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Invisible loco

Postby Rockdoc2174 » Fri Sep 23, 2016 8:55 am

This isn't the usual plea for an explanation of why a reskinned loco doesn't appear in the game but a question about whether it could be done deliberately. We can't simulate gravity shunting in the game so iconic things like hump-shunting yards can't feature properly. Another area where gravity was used was under the screens at collieries. Locos were never, ever allowed under them. Their exhaust would have made working conditions intolerable inside, risked setting them on fire or, at best, damaging the equipment. Wagons were pushed into storage sidings via a track that did not pass under the screens (where the red marker is on the linked OS map for Babbington Colliery on the outskirts of Nottingham) and they were then fed under the screens by gravity, via a weighbridge to record the tare weights, filled and reweighed before being assigned to one of the interchange sidings. We can't simulate any of that unless we have a loco involved but no loco ever went under the screens. We can ignore that stricture but it bugs me as an ex-NCB employee.

Is it possible to create an invisible loco, with invisible couplings for preference, that could be used with AI to give the effect of wagons moving under gravity? If so, would anyone consider knocking one up and uploading it to UKTS? I know that one is included in Wherry Lines and is used as a route blocker but (a) I don't know that it can be couple to anything and (b) I'm loath to add another commercial dependency for just that item. This one doesn't need to be very big, in fact the smaller the better so that when they take wagons into the interchange sidings they have as little impact as possible.

Keith

https://www.old-maps.co.uk/#/Map/453238 ... /13/101329
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Re: Invisible loco

Postby AndiS » Fri Sep 23, 2016 9:31 am

It is easy to have an invisible loco, just ask one of those who did not get their downloaded reskin working. :lol:
So, seriously, yes, you can link to blueprint to some invisible shape, underground shape, or nothing at all (maybe). Same for the coupling.

What you cannot influence is the coupling of the wagon next the invisible loco. It will couple - or else the AI will crash.
So what you need is an engine with the shape of a wagon!

This would work find for slowly moving a rake of wagons along some track (under screens or whatever).

Hump shunting is more difficult as you would need a ton of AI-only, i.e., invisible, block signals all over the hump. Even then it would not work because the stock that is uncoupled from AI becomes dead. It would be tempting to have a consist of 10 engines that look like wagons go up the hump and then each of them uncouples. But only the first would have destination set. You can't have AI trains that split and go to different directions.
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Re: Invisible loco

Postby brysonman46 » Fri Sep 23, 2016 10:07 am

If you stop on a rising incline, and then release the brakes, the whole consist starts to roll backwards (or on a down gradient, roll forward). What I have not tried is, with the loco brake on, to release the brake on the final wagon and uncouple. If that will run downhill, then the first part of the problem is solved. The second half of the problem is getting the wagon to stop at a required destination! Once that is solved, one should be able to release wagons one at a time (I think!)
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Re: Invisible loco

Postby brysonman46 » Fri Sep 23, 2016 10:14 am

Another thought. Could wagon arresters (devices to brake a free rolling wagon) be created using a similar algorithm to that which is used for the TPO carriages load/unload track mechanism?
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Re: Invisible loco

Postby Rockdoc2174 » Fri Sep 23, 2016 10:30 am

It's already an interesting discussion of the topic and I really like Andi's idea of a self-propelled wagon. With the technology available in the mid-fifties, I'm not sure that it would be possible to have a number of wagons roll over a weighbridge without stopping but one wagon at a time, travelling slowly enough, might give enough time for the operator to read the wagon's ID number and its weight. If we assume, for practical reasons in the game, that wagons go under the screens one at a time, if we could make them stop and load under the screens in AI (I guess that's possible?) it could look absolutely superb.

Next question: can an existing model be adapted to move itself or does it need a new model? For the Friargate Line I would say that we'd need a fitted and an unfitted 16T wagon and a seven-plank wagon with several faded ex-private owner liveries. We have a number of different wagon models from Woodhead and Weardale. If we can adapt an existing model, would it be as simple as copying an existing wagon to a new folder and replacing a file?

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Re: Invisible loco

Postby VictoryWorks » Fri Sep 23, 2016 10:48 am

The TPO is all lots of smoke and many mirrors, I can't think of anything in there that will help with this piece of magic beyond the idea that you just need to make the player see what you want them to see; how it happens is kind of irrelevant :-)

There's no problem in re-using an existing wagon and just attaching the parts to a loco blueprint instead of a wagon. It can be any type of powered loco as it's only going to be AI "driven".
You can then use this to either pull other wagons, acting as the lead wagon, or on it's own. It's then just a case of getting the dispatcher to move it slowly to X location, sit there for a bit, and then move on.

And as I type this, maybe I'm wrong about my first sentence as there is some detail from the TPO you could use!
You could place a hidden signal at the track side which sends a consist message that says "I am next to the coal filler thing, do something!". The wagon (which is really a loco!) script can pick this up and run the animation that moves the coal object in the wagon from hidden in the floor slowly up to the top. This would work for a single wagon. For multiple wagons you'd need to make it a bit more complex where multiple signals placed at 1 wagons spacing could send messages that would be passed by the lead wagon down the consist telling each wagon to fill in turn as the front wagon stops at the next marker.

I think editing a wagon to make it an AI loco is the first step. Then you need to have a play with a bit of track and some markers and see what you can convince the dispatcher to do.

I would also suggest that if this operation is only ever going to be scenery without the player involved then I would disconnect the track (you can have it visually lined up, just make sure it is not actually connected on the track diagram) as I can't help but think it might help the dispatcher not to have a breakdown if this isn't connected to the main network the player and other AI is using.
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Re: Invisible loco

Postby Rockdoc2174 » Fri Sep 23, 2016 11:05 am

VictoryWorks wrote:I would also suggest that if this operation is only ever going to be scenery without the player involved then I would disconnect the track (you can have it visually lined up, just make sure it is not actually connected on the track diagram) as I can't help but think it might help the dispatcher not to have a breakdown if this isn't connected to the main network the player and other AI is using.


Most of this could be classed as scenery but not all of it. Taking the pits on the Friargate Line, at Stanley the screens are visible from the main line but at Gedling and Babbington they would not be. There will be enough track at Babbington from the GNR and MR lines and at Gedling from the GNR to make shunting scenarios practical at both so we could have trains of empties being delivered and a colliery loco taking the empties and moving them to the storage sidings on the west side of the screen via the screens by-pass line and, taking loaded wagons - not the self-propelled ones - and making them up into train lengths for the main-line locos to take away.

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Re: Invisible loco

Postby brysonman46 » Fri Sep 23, 2016 11:30 am

Regarding my proposed "solution". Have tried on my test bed to simulate a "wagon rolling" situation. On a gradient of 1 in 30, a loco and 3 wagons stopped on the upgrade. Release the brake and they all roll backwards. Uncoupling one or more wagons and applying the loco brake lets the wagons roll about 10 metres, then come to a halt. Seems the despatcher is no longer interested in them, whereas they should be accelerating down the slope. So no joy there on the "simple solution"

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Re: Invisible loco

Postby AndiS » Fri Sep 23, 2016 12:29 pm

Nick, this is about what I found many years ago: When you uncouple something from a moving player train, then the physics are simulated fine. But as soon as the uncoupled consist comes to a halt, physics are switched off.

I seem to remember that when you uncouple (as a slip coach) from an AI train, then the uncoupled part comes to an immediate halt? But not sure about that. There was not too much potential in that as AI crashing another vehicle always lead to insane reactions even when it would be a soft bump of the buffers.


Keith, I never tried loading instructions with AI, but your example with the screen sounds like each of the wagons should get "load" instruction for the bulk loading facility there. Then the AI should stop for some time for each of the wagons in turn.

Like Pete said, automotive wagons are just any wagon plus any engine blueprint where you set maximum speed to a few mph and maximum force to something smallish to prevent rocket starts.


If the iterative loading of an AI train does not work as planned, you would need to resort to the scripting scheme that Pete suggests. But aligning with each of the wagons would need extra care and altogether, it could become quite some project. And remember that AI does not receive the signals Pete mentioned. So the AI train would need a series of stop-at instructions, spaced by a wagon's length. But then, the "signal" could start the loading animation whenever it sees that a train stopped under the screen, without any sending of a signal. But the rise of the load level could not be implemented. This is a property of the wagon and if it does not receive messages, it will not cooperate.


Regarding the co-existence of AI and player trains, you need to try each case. I have seen many cases where AI panicked and fell into 0.5 mph zombie crawl although there was really no reason, because there were sufficient signals between player and AI.

So if there is a rake of tracks where the player shunts, a nearby AI consist inching forward under the screen may or may not panic. It seems that they panic less if you approach them from the rear. What they hate is a player in the 6 or so blocks ahead of the AI engine, even if it has orders to reverse and never go where the player is. It may help to set the (final) destination of the consist under the screen to the end of that track. Then even the AI dispatcher should see that no one crosses the path of the AI train.
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Re: Invisible loco

Postby VictoryWorks » Fri Sep 23, 2016 12:47 pm

Ah well done Andi, I forgot about AI not receiving signal messages.. that is a constant annoyance when trying to be clever :lol:
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