Tvm Is A Buggy Mess

Discussion in 'TSW General Discussion' started by nielsmallant100, Dec 20, 2020.

  1. 7orenz

    7orenz Well-Known Member

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    Cause my "limited" English language I tend to do basics and generic examples. I know there are differences between a steady or flashing code, like also between a green or diamond or black border/background code.
    Like I said (and repeaterd) since my 1st post about the new TGV route, after several runs, the only TVM difference I noticed with the Train Simulator version and also with the real life TGV cab rides, is the 000 before the station stop. All the other aspects, about the TVM, looks pretty good (obviously imo).
     
  2. stujoy

    stujoy Well-Known Member

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    There’s a bug report for this with a video that shows what should happen. It is not what happens in TSW.

    From post 3 in the bug report thread and the next two posts there is a good explanation of the difference between the game and real life. In the video, you can watch from 12 minutes to 20 minutes and see what should happen and see the driver happily doing what would cause an emergency brake application in the game.

    https://forums.dovetailgames.com/threads/tvm-430-not-working-as-intended.32692/#post-223489
     
  3. geloxo

    geloxo Well-Known Member

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    Sorry but I see the video and find the same result as in game and the same what is described in internet about TVM: when driver gets a flashing he adjusts the speed to reduce to that limit and prepares for next speed reduction, staying below flashing speed always unless a steady indication is given. Only in that case driver accelerates. You can see that at 17:30 to 17:45 as the traction sound is cut and electric brake starts (you can hear the noise of the power lever passing to OFF position). In the cases where train speed is slightly above a flashing limit it´s always below the +10 or +15 km/h threshold, which is the tolereance for a brake application activation according to the information about this system on internet. I have tested that tolerance indeed today and brakes are not applied unless you overspeed more than 15 km/h for higher speeds or more than 10 km/h for lower ones.

    The only problem I see on video is at 18:20, as when the 230 limit is is force train is at 257, so +27km/h above limit, but still braking, so maybe that´s why emergency brakes were not triggered. The same at 19:45 with the 160 limit where current train speed is 215, so +55 km/h above limit but again still braking. That happens also with the LIRR route safety system where brakes are not applied even if you overspeed the block speed provided that you are braking with enough deceleration (40-60% brake power in game). I don´t know this system in real life to judge if this is allowed or not, but apparently system didn´t react, so it seems to be allowed.

    Honestly I can´t vote for a correct/incorrect implementation in game or decide if they adjusted anything on their own, but the block speed limit principles they used are correct from the point of view of my signalling knowledge from other systems like LZB or ERTMS in real trains and the information available from this system. At the end of the day most systems are working in a similar way. ERTMS is based on movement authorities which are basically also block based speed limits with a target speed and a target distance to meet that speed. I don´t know if those overspeeds are allowed. What I know is that ERTMS would have triggered an emergency brake if you are +15km above limit for sure. But TVM system is new for me as well.

    Cheers
     
    Last edited: Dec 24, 2020
  4. stujoy

    stujoy Well-Known Member

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    This is exactly the point. In both those cases the speed limit isn’t in force yet and the train is not above the limit. It is only above the limit which is to be applied at the following flag, so of course those higher speeds are allowed. If you were to do the exact same thing in TSW2 you would get an emergency brake application because TSW2 is applying the speed restriction too soon. What you are in effect saying is that TSW2 is right and the real life driver is wrong based on what you think is supposed to happen.

    The whole thing with this thread is because those who don’t know the system are believing TSW got it right, and those who do know the system are trying to explain it but for some reason are not being believed. You can actually see it in this video but you are now trying to make what happens in the video match with your own initial belief by wrongly assuming that it’s because the driver is braking with enough deceleration. That’s not even part of the system. How can you say that if by your own admission you don’t know the system? How can you go on contradicting those who do know the system if by your own admission you don’t know the system and add guesses to your own explanation to make it fit? What the LIRR safety system has to do with this is anyone’s guess, totally different system and irrelevant.

    I didn’t know the system well before all of this but I know enough to know it’s wrong in the game, because I’ve read the Wikipedia page, seen videos of it working correctly and read the descriptions on here from people who know what they are talking about, which all match. Then there are the people, not just you, saying the game has it correct, whose explanations are contrary to what the Wikipedia article says and what you can see happening in the actual cab in the videos. Initially I was only seeking confirmation of what was happening in the game to see if it was indeed wrong, but have ended up in the middle of a big debate about how the system is supposed to work. It’s unbelievable. That shouldn’t still be up for debate.
     
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  5. geloxo

    geloxo Well-Known Member

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    Ok, let´s try to do a test to replicate what is seen on that epic video while we try to learn more about this system and the route :D. The basic rule is that system applies brakes if we are 15 km/h above limit. This is the brake application threshold for TVM I found in the system documentation on internet.

    1) First case: 320 to 300 transition.

    300 in force but we don´t brake --> brakes applied by TVM as soon as train is at 315 km/h (so 15km/h above limit) --> Correct behaviour

    01.png

    2) Second case: 230 to 200 transition (similar case as in the real video)

    +25km/h above limit but braking manually --> brakes not applied by TVM as seen in the video, even if we are above the +15km/h threshold that triggers brake application --> Correct behaviour

    In the picture we don´t see the flashing 200 at the point the shot was taken, but we can see the limit in force in the HUD speedometer.

    02.png

    3) Third case: 200 to 170 transition

    +30km/h above limit and still braking manually as in case 2 --> brakes applied by TVM --> I would say correct as well provided that either deceleration was not enough or threshold was much higher than in the second case, so that´s why brakes were applied in this case. This is to be confirmed by somebody familiar with real TVM, but indeed it does the same as the LIRR route safety system, which was my initial assumption. So to me this is also correct and it has also sense in terms of signalling safety.

    03.png

    Cheers
     
    Last edited: Dec 25, 2020
  6. stujoy

    stujoy Well-Known Member

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    I’m giving up, you still don’t get it.
     
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  7. geloxo

    geloxo Well-Known Member

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    Please share the documentation you had seen then mate. I´m not trying to tell anybody I´m right, only trying to understand the system as anybody else here. I just gave my opinion about what I saw on the video, what I see in game and what I know about real signalling systems I had worked with, and always stressed I don´t know the real TVM system to judge if it´s correctly implemented or not but according to the info I saw they did it at least as it is described in internet.

    I just checked this:

    Transmission Voie-Machine - Wikipedia

    And there I see what game implements:

    1) "A digital display on the train driver's dashboard shows the maximum permitted speed for a train's current block" --> same as DTG did, same as real driver follows in the video and same I could see on my own tests in game.

    2) "When a block is followed by a more restrictive (slower) block, the display for that block flashes so the driver can better anticipate the speed change without releasing the brake. Restrictive indications can only be updated at block boundaries, except in emergencies. They are accompanied by an audible in-cab horn signal" --> again same as seen in video and game

    3) Brake application thresholds included in the wiki table also match to what I have seen in tests (+15 km/h)

    My only doubt was why brakes were not applied when being above the limit in force for the block, and there is where I just gave my own opinion stressing that it was just my assumption. Please feel free to correct whatever is wrong. I just want to learn about this system :D

    Following those indications I just played the 7am service without any problems. Speed was correct according to the limits without having any brake application and arrived in time to both stops...

    TS2Prototype-Win64-Shipping 2020-12-25 02-46-55.png

    Cheers
     
    Last edited: Dec 25, 2020
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  8. Callum B.

    Callum B. Well-Known Member

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    Someone linked this TVM430 guide earlier, and I do recommend reading the aspect explanations as they are quite helpful. However I did notice a bit of an irregularity in the example drawings. I would like to preface that for each of these explanations I am not referring to the penalty brake line being drawn as it misrepresents how TVM works (it is not a continuous brake curve like LZB). Also the penalty speed for any 230km/h block is 245km/h, not 235km/h as said in the illustrations. The original creator made a few typos, more on that below. Each step is with respect to the TVM aspect given.

    First:
    [​IMG]
    This follows very logically. For each flagpost:
    1. The train is cruising at 320km/h. (Current penalty is at 335km/h)
    2. The train is cruising at 320km/h, but is warned that the next aspect will ask to reduce speed. (Current penalty is at 335km/h)
    3. The train is cruising at 320km/h but immediately begins slowing down to 300km/h, expecting a further reduction at the next signal. (Current penalty is at 335km/h)
    4. The train has slowed down to 300km/h but now begins slowing down to 270km/h, expecting a further reduction at the next signal. (Current penalty is at 315km/h)
    5. The train has slowed down to 270km/h but now begins slowing down to 230km/h, expecting a further reduction at the next signal. (Current penalty is at 285km/h)
    6. The train has slowed down to 230km/h but now begins slowing down to 170km/h, with no further expected speed reduction. (Current penalty is at 245km/h)
    7. The train has slowed down to 170km/h and will continue at this speed until the next signal change. (Current penalty is at 185km/h)
    8. The train has clearance to return to 320km/h cruising speed. (Current penalty is at 335km/h)
    For each of these steps I have labelled the penalty brake threshold speed in text. For example, if a driver is following the TVM instructions in step #5, they should not be penalised for travelling 230km/h at the beginning of the next block because the system has not yet told the driver what the next speed reduction is. This all makes sense.

    However there is a discrepancy in this second example:
    [​IMG]
    If we go through the steps here:
    1. The train is cruising at 320km/h. (Current penalty is at 335km/h)
    2. The train is cruising at 320km/h, but is warned that the next aspect will ask to reduce speed. (Current penalty is at 335km/h)
    3. The train is cruising at 320km/h but immediately begins slowing down to 300km/h, expecting a further reduction at the next signal. (Current penalty is at 335km/h)
    4. The train has slowed down to 300km/h but now begins slowing down to 270km/h, expecting a further reduction at the next signal. (Current penalty is at 315km/h)
    5. The train has slowed down to 270km/h but now begins slowing down to 230km/h, expecting a further reduction at the next signal. (Current penalty is 285km/h)
    6. The train has slowed down to 230km/h but now begins slowing down to 170km/h, with no further expected speed reduction. (Current penalty is 245km/h)
    7. The train has slowed to 170km/h and will continue travelling at this speed, expecting the next block to also be 170km/h, but then a more restricting aspect after that. (Current penalty is 185km/h)
    8. The train is still travelling at 170km/h but the new aspect tells the driver not to exceed 80km/h in this block. Because the penalty brake threshold for this signal is 90km/h, the emergency brake would be applied.
    [​IMG]
    upload_2020-12-24_19-1-25.png

    This does not follow logically and I think the creator made an error here. There are a few other mistakes on the page as well that I think they made while copying and pasting (such as black 220 and black 160, you can see simple errors made on both of those).

    I think that the second illustration is missing a solid diamond 80 between step #7 and step #8.
    upload_2020-12-24_19-1-59.png
    (Please note that the COVIT footnote is referring to the penalty of the next block. The penalty limit in the diamond 80 block is the same as the previous.)

    Other than that, I think the page is very helpful. Green and black indicate current maximum travel speeds, with green generally indicating high cruising speeds with black indicating temporary speed restrictions. White diamonds indicate when to begin slowing down and to which speed to slow down to, but no new speed penalties should yet be enforced. Only after the white diamond has turned to black should the new speed restriction be enforced by COVIT.

    Hopefully this post has been helpful or elucidated TVM a bit. In cab ride videos on YouTube, TGV drivers may be more proactive or careful in their driving so they may slow down sooner than they might have to, but these are the rules of TVM as the rulebook would explain. :)

    Cheers
     
    Last edited: Mar 9, 2022
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  9. heardturkey

    heardturkey Active Member

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    Quote from Callum B:
    Hopefully this post has been helpful or elucidated TVM a bit. In cab ride videos on YouTube, TGV drivers may be more proactive or careful in their driving so they may slow down sooner than they might have to, but these are the rules of TVM as the rulebook would explain. :)
    I think that may sum up quite well why people are getting these emergency brake problems. Most of them seem to complain that they were at the maximum speed that (should be) allowed and not anticipating further restrictions ahead.

    I have run several of the services and all of the tutorials and am never getting an emergency brake applications.

    On the bad things happen scenario, I managed that 1st time, no emergency brake applications, arrived at the intermediate station 4 mins early, and drove pretty much all the way following the speed limits by driving cautiously.

    My passengers congratulated me on a pleasant journey with no whiplash injuries reported :)
     
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  10. geloxo

    geloxo Well-Known Member

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    Thanks for the explanations. About the continuous curve for speed supervision this is correct for TVM-430, as it does that supervision and this is also explained in the wiki I checked.

    The important data that trackside sends to onboard is the following, according to wiki:
    • Speed Codes containing three pieces of information: the current maximum safe speed in the block, the target speed at the end of the block, and the target speed at the end of the next block. Each of these can take on six different values; in the case of a high speed line these are (in km/h) 320, 300, 270, 230, 170, 80 and 0, roughly corresponding to a typical braking and deceleration profile.
    • Gradient information, averaged over the length of the block. This allows the train's signalling computers to account for this in speed calculations.
    • Block Length, which can vary quite a bit, and is also important in speed calculations. For example, on a flat stretch of high speed track, a block can be a full 1500 metres long, while in the terminal areas of the Channel Tunnel, blocks are one-tenth as long.
    What onboard does with this data is the following, according to wiki again:

    In older versions of TVM, the target speed was updated only at every block boundary, resulting in a "staircase" style speed profile which is not representative of the continuous speed changes effected by the driver. However, with the additional information of block length and profile, TVM-430 is able to generate a continuously varying target speed through calculations performed in the onboard signalling computer, thus giving a much more realistic speed profile of continuous acceleration or deceleration for the driver to follow

    So modern TVM-430 is able to draw a continuous braking curve for speed supervision as LZB does, because it has the speed limit for the entry point of current block, the block length, the averaged gradient inside the block, the target speed at the current block end and also the target speed at the end of next block. But it does not represent the changing permitted speed in realtime to driver as LZB does. Instead of that it only presents the predefined speed limits (320, 300, 270, 230, 170, etc) and tells you if the speed will be further reduced or not. That´s an alternative way to display a braking curve indication but less intuitive than the continuous speed change method displayed by LZB. The reason behind that approach can be the typical in such cases I have seen in other signalling systems used at different countries: backwards compatibility with lines using older trackside versions of TVM, with rules/regulations or with driving instructions/rulebooks. In this case compatibility between newer versions of TVM with the older ones (the ones using the staircase speed profiles approach).

    I think that´s why the original author on the page containing the drawings included the continuous curves on it, as they indeed exist in the internal calculations the onboard does, even if they are not displayed to driver.

    And now the part of the discussion disagreements or where we are getting the confussion (at least what I didn´t understand properly in the beginning): cab indications and where limits shall be in force. I have read the original french page linked by you guys and there it explains the main rules:

    - Steady green: max allowed speed for the block where train is and no further reduction expected at the next block. Used at mainline top speed areas. If displayed speed is overpassed brakes are applied.

    - Flashing green: max allowed speed for the block where train is and announcement of a further reduction at the entry to next block. Used at mainline top speed areas. If displayed speed is overpassed brakes are applied.

    - Steady diamonds: max allowed speed at the entry of next block (not at the block the train currently is) and no further reduction expected afterwards. Used during approach to lower speed limits (for instance stations stops or when traffic is ahead). If displayed speed is overpassed at the entry to next block brakes are applied.

    - Flashing diamonds: max allowed speed at the entry of next block (not at the block the train currently is) and further reduction expected afterwards. Used during approach to lower speed limits (for instance stations stops or when traffic is ahead). If displayed speed is overpassed at the entry to next block brakes are applied.

    - Steady black: max allowed speed for the block where train is and no further reduction expected at the next block. This is used at areas where line speed limit is below regular top speed limits for the line (for instance a diverging route to a station platform, a curve or a tunnel). If displayed speed is overpassed brakes are applied.

    - Flashing black: max allowed speed for the block where train is and announcement of a further reduction afterwards. This is used at areas where line speed limit is below regular top speed limits for the line. This would be used, for instance, at a diverging route to a platform stop followed by another diverging route that had a lower limit than the first one (we don´t have this case in game). If displayed speed is overpassed brakes are applied.

    Is this the correct interpretation of cab indications and where the limits shall be in force (current block or entry to next block)?

    Cheers
     
    Last edited: Dec 25, 2020
  11. hightower

    hightower Guest

    This is why TSW needs better tutorials and manuals. The one for M2A is good, but it could and probably should be better.
     
  12. geloxo

    geloxo Well-Known Member

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    Well I repeated yesterday´s tests and did nothing with brakes as instructed by stujoy as this is clearly not applicable for this system. See results:

    1) Announcement for speed limit at the next block (diamond): same case as in the youtube video indeed except that there it was a 160 if I´m not wrong. But I managed to reach +50km/h overspeed as in the video. Brakes not applied in game, as seen in the video.

    01.png

    2) Speed limit in force for the block that was announced before: only after passing the board the 170 is in force an there is where brakes are applied.

    02.png

    The greens I already tested yesterday and you can see that brakes were applied as soon as +15km/h was detected. That was correct as green is the speed in force for the block you already are.

    I don´t know where you guys get the brake applications but all I see in game is a correct implementation and also matches with what we see in the real videos. Yes the HUD speedometer shows the speed restriction before but the brake supervision is not triggered until it has to be triggered. Maybe they just follow an easier implementation for them, I don´t know, but it does was it has to do. The manual also describes those limits as they are expected to be. Maybe some clarifications could be added, such as where brakes will be applied, but I mean... DTG did the implementation that was expected according to the available information we have shared here... If someone else still gets brake applications where they shouldn´t be please comment them anyway.

    I must also say that the sound implementation for the train inside the cab is one of the best I have seen so far. You can notice even the small changes when accelerating/braking and the wheels vibrations typically produced by high speed trains on rails without joints like these ones.

    I reported some minor errors with KVB display and I also think the boards at Marseille are either missing or not well illuminated but the overall DLC quality is very good.

    Cheers
     
    Last edited: Dec 25, 2020
  13. Callum B.

    Callum B. Well-Known Member

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    Yes, your explanations of each type of aspect look correct to me. As for the continuous curve, you are technically correct. But I phrased it as such because, like you said, that information is not enforced to the driver in real-time like LZB. Only at certain time/signal intervals. :)

    I think this is done for players who want to follow the speed targets on the HUD. I think the issue is that the points system treats going over the target speed as "overspeeding" when in reality that target speed is not enforced yet. I think this is just because they do not have a separate teardrop for "advised speed" and instead are just using the "target speed" pin from LZB. But, if the TGV itself is operating correctly and not penalising the driver when driving correctly, I think it is mostly a non-issue.

    Cheers
     
    Last edited: Dec 25, 2020
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  14. geloxo

    geloxo Well-Known Member

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    Nice to read that. Step by step we are getting to the right end understanding this system. At least I have a clearer picture today :o:)

    I have also noticed that TVM isolation switch (at the panel behind driver) still allows indications when system is isolated but brake application is what gets isolated. I sent a ticket just in case cause I think it should be completely off as KVB is when isolated, but who knows... Anyway if somebody does not get brake applications please check that system was not isolated (isolated it´s the default starting state for services).

    Cheers
     
    Last edited: Dec 25, 2020
  15. Callum B.

    Callum B. Well-Known Member

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    Matt mentioned on stream a few times that this is the intended behaviour because it's not really possible to drive the route with TVM off completely. So instead of worrying about the penalty speeds and exact behaviour of TVM, a novice driver can just look at the numbers and not worry about anything else. That's a good design feature, in my opinion, even if it breaks away from the realism of isolating TVM.

    Cheers
     
  16. Monder

    Monder Well-Known Member

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    I wouldn't consider myself a novice driver, but I guess this is now also a solution for us more experienced. Drive with isolated TVM, follow the way it is SUPPOSED to work and give yourself a slap if you don't manage to slow down properly :D at least until they fix it and make it work correctly.
     
  17. geloxo

    geloxo Well-Known Member

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    Yeap that makes sense as indeed there´s no visual signalling to use. Only problem I saw on some scenarios was that displaying of speeds happened even at Marseille platforms which I doubt is correct as there´s no TVM trackside devices there. In services it works well and isolated or not system is not active until the tunnel.

    Cheers
     
  18. joulz75

    joulz75 Active Member

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    From what I saw in a cabride on the LGV med between Avignon and Marseilles, and commentated by the driver himself, he said that he always keeps a safety margin (with a step forward), so for a flashing 270 he would reduce speed up to 230. Actually the behaviour in the game is like irl :)

    This is a paying video and it's in french haha, but if you're interested, you can find it here : https://www.railpassion.fr/videos/rp143-cabine-dun-tgv-duplex-de-lyon-part-dieu-a-marseille-saint-charles-2e-partie/ (around 11:00 for the explanation)
     
    Last edited: Jan 2, 2021
  19. Callum B.

    Callum B. Well-Known Member

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    How drivers operate and how TVM operates are two different things, and conflating the behaviour of drivers to the proper enforcement by TVM is what is causing the confusion in this thread. Drivers operate more carefully than TVM penalises, but that does not mean that TVM in the game should penalise players for not driving as carefully as they would in real life.
     
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  20. joulz75

    joulz75 Active Member

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    Sure, I agree. But at least if we want to act true to reality, that's not so bad...
     
  21. Callum B.

    Callum B. Well-Known Member

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    Acting true to reality would be implementing a TVM system that simulates real life TVM. ;)

    Cheers
     
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  22. Tanglebones

    Tanglebones Well-Known Member

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    It just blows my mind that there is no tutorial in game on this, we're all left to look at Wikipedia and videos to try to figure it out ourselves. All that development budget and time, the consultations with SNCF, all the testing, and no one thinks to write a short in game tutorial along a 10-km or so section of track explaining this system and giving us some hands on. It's like building an Apollo capsule and letting the astronauts figure it out themselves...two steps forward and one step back, IMO. Yes, I get that people love figuring it out, but really. This is fundamental to enjoying/understanding the route.

    Just my two pence.
     

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