TLDR:
Minecarts can derail if at least 2 are on same track, bump each other and possibly accelerate (needs more testing)
Reproducible for Minecraft 1.13 snapshots (noticed in 17w50a), confirmed for 1.12.2 by @unknown and @unknown
Derailing happens in the curves of a track
Derailing (of 1 of 2 carts, 1 containing an entity incl. player) seems to only happen with rails laid out inEast-Westdirection, unless you have 3 carts on a track inNorth-Southdirection; derailing positively confirmed in this case for 2 carts containing mobs, 1 cart empty-
Currently unsure about directionality, in 1.15.2 pre-1, derailing happens for me at the moment solely in North-South-direction, if 2 entities are in a minecart, one can derail. (needs more case testing)Derailing does not seem to happen if it's 2 carts only (with no entities) on a track as it seems you can't make them accelerate/not bump each other enough ❓ , they rather seem to drive together like train waggons (needs more testing)
Empty carts which are on neighbouring rail lines, laid out East-West show a different behaviour than empty carts on neighbouring rail lines, laid out South-North; it seems the minecart collision box differs here, see video:
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Also empty (not containing an entity) Minecarts can derail if there are at least 3 of them on a track;
this includes also the North-South-direction.
Currently suspected this is the case because in this setup they may not all be driving in the same direction, but one of them will be driving in the opposite direction, and the upfollowing "bumpings" or suspected accelerations ❓ may propel one of the carts out in a curve.
The same suspected accelerations ❓ seem to be happening if one of the carts stops and gets bumped by one of the others.
Because of MC-92165 I host I've got various different cart test tracks spread on my several bug test worlds; I noticed a derailed cart in 17w50a and after conducting some simple tests, this can be reproduced relatively fast. Use
[media]in 17w50a or
[media]in 1.12.2 to test it yourselves.
The derailing of 2 carts on same track only, one containing an entity (incl. player), seems to be directional (but needs more testing to be sure).
Short video proving this behaviour with one test conducted, see above.
Longer video with several tests in the same manner can be watched here: https://youtu.be/NdC3-KfTXls
I also noticed that when carts bump into each other, they seem to be more prone to simply stop their movement if rails are laid out in East-West-direction. This happens usually at the curves of a track (watch also Youtube video to see it in action).
I currently didn't see any derailing when it was 2 minecarts only, with no entities inside one of them, but more tests have to be conducted to verify this. This may be because of a needed gain in acceleration of a cart for derailing, which seems to happen by "bumping" into each other, which seems to be more often the case if one of them holds an entity (maybe due to the entity's hitbox sometimes bumping the other cart into the other direction).
Note that in the test track the 2 rail lines got no gap between them, which could maybe cause an interference between the minecart's and some entities' hitboxes.
Derailing happens in the curves of a track, same like the carts sometimes stopping their movement after bumping against each other.
Currently, I don't seem to be able to reproduce the derailing (pig in 1 cart, 1 cart empty) if the tracks are laid out in North-South-direction.
The stopped movement of the cart also seems to occur much more rarely with North-South rail tracks.
Needs more testing.
Additional info by @unknown:
If you build rails like in the picture with a mob in a minecart on it and the player stands inside the "rail ring" at the height of the mob collision box, he is pushed around. It does not happen with just the minecart or outside the "rail ring". The effect is more visible when you fly.
The player is pushed around when the minecart is in the N / E (white) corner and the player is in the area of the white blocks.
The player is pushed around when the minecart is in the N / W (black) corner, and the player is in the area of the black blocks.
As you can see in this video:
Related issues
is duplicated by
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Panda4994
Can confirm for 17w50a.
You can use
to reproduce it. (Side note: It was a bit tricky to build this file for reproduction because of MC-103452)
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I have been able to reproduce this several times with a mooshroom or pig in the mine cart, and tracks in the east/west direction in version 1.12.2.
I could not reproduce when using a villager in the mine cart. Added image X-2017-12-19_11.21.45.png
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Thank you Xavom, I guess all "chubby" entities will have that issue, I'll add a size chart now so we can find out the "breaking point" 🙂
I hope the size charts in the wiki are all correct/up to date, and there haven't been any changes in entity sizes between 1.12.2 and 1.13 snapshots.
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Can confirm in 1.12.2 derailing with the following:
Cow
Sheep
Guardian
Llama
Mule
Squid
I have tested others as well, but I cannot rule them out. For example the donkey I tested and was unable to reproduce the derail, yet with the mule is on the 2nd try. The mooshroom was quick while the cow took more than 10 attempts.
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Upon further testing, it seems it could be a different issue than initially suspected, I updated the bug description a bit and will look more into it as soon as I find the time for it again.
No need anymore to test different entity's hitboxes for 1.12.2 or 17w50a, thank you for you Xavom and Panda4994 who helped 🙂
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Wanted to do a separate bug report first, but I think it's the same problem as in this bug report here.
If you build rails like in the picture with a mob in a mincart on it and the player stands inside the "rail ring" at the height of the mob colision box, he is pushed around. It does not happen with just the minecart or outside the "rail ring". The effect is more visible when you fly.
[media]The player is pushed around when the minecart is in the N / E (white) corner and the player is in the area of the white blocks.
The player is pushed around when the minecart is in the N / W (black) corner, and the player is in the area of the black blocks.
As you can see in this video:
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Thank you Unary 🙂
So it really seems to be directional and only happening in curves, like I observed as well.
I'm currently just not sure about the acceleration/bumping thing, and even less now that I see your setup, but then again in my case it's about the derailing specifically, and there seem to be several prerequisites needed that causes it.
I suspected before the size of the entity/hitboxes could play a role as well, so I started adding a huge list of all entity sizes, but I'm not so sure anymore after some tests turned out not as I expected them and concluded there must be more to it than just hitboxes.
In case you fiddle more with it and find out anything more, feel more than welcome to say so, I currently am a bit under stress time-wise 🙂
Have a good weekend!
Panda4994
Can confirm for 1.13pre3.
Panda4994
Confirmed for 1.13pre4.
Panda4994
Confirmed for 1.13-pre6.
Panda4994
Confirmed for 1.13-pre7.
Panda4994
Confirmed for 1.13-pre8.
Panda4994
Confirmed for 1.13.
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Perhaps this bug is somehow related to MC-80895, for the latter is also able to be caused by collisions on curves of tracks.
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Confirmed for 18w50a.
Perhaps this is caused by the minecart hitbox being offset in the direction of the curve while, and even before, traveling through it. Placing a wooden pressure plate (or a hopper to draw items out of a chest or hopper minecart) at the inside of the turn confirms this. While this being a nice feature when needed, for me it seems more of a problem.
If this is the case, maybe a solution would be to force the hitbox alignment to the x,z center of the block the track is on, while rendering the minecart along the center of the curve. Maybe a slightly smaller hitbox along with this could provide additional benefit.
Is there a non-toxic forum to discuss these issues?
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@unknown Mojira-Reddit I would say?
Could you please wrap your PNG like so, to minimize it optically? 🙂
! 2018-12-14_11.35.00.png|thumbnail !
(no blanks between the "!" and the rest of the text)
(You need to add a "|thumbnail" after the png name as well. Sorry for the notifications @ watchers)
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Minecarts seem to stick together (MC-142045), with and without entities, including players, thus testing for this bug here may be currently a bit problematic.
Tests in 1.13.2 show that the carts already can stick together, in both directions (SN+EW); I apologize that this has been overlooked, but I haven't confirmed this bugpost (or any of my bugposts) myself for quite a while due to real life obligations.
Will conduct more tests with other setups eventually, but just heads up for you, in case you may run into this issue yourself.
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Affects Version/s: 1.15 Pre-Release 3, 1.15 Pre-Release 4
pulpetti
Affects 20w29a
[Mod] Jingy
This issue is cannot be reproduced with the 24w33a+ minecart experiment:
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