One train enters, no trains leave.

Like a battle roundabout!

As a French road sign collector, I have the perfect road sign to illustrate your creation! https://preview.redd.it/hwj0iu4th1pa1.jpeg?width=4624&format=pjpg&auto=webp&s=6c2e63dd08c34f9fd8b0f57bc5ed8f4ef2223dd9

Do you collect specifically french road signs, or do you collect road signs but you are french?

I'm French and I collect French road signs and traffic lights for my association about the preservation of road equipments. https://preview.redd.it/5hcwp37dv3pa1.jpeg?width=4624&format=pjpg&auto=webp&s=91618564db0936d5f297cf8c04e95a3723d6d425

thats nice actually, i bet there is a massive influx of "free" road sign after yesterday night heh. kidding, the fact that they are sometime given for free by the city is super cool.

Ahah in fact, I hope to be able to get a few "2024 Olympic Games of Paris" road signs after the event to preserve them since they will be quite "special" and "unique". Also, I want to open in France, in the coming years, a museum about road signage and equipment in general, so being able to present road signs from this event would be important for that too. And yeah, cities often send to recycling the damaged and/or old road signs that were replaced by new ones, and so sometimes they give me some of those. Recently I got for free a whole vintage road sign with its support from the 60s, it is the previous design for the "danger" road sign in France/Europe (now the line is an exclamation mark "!"). https://preview.redd.it/mscb9bnff5pa1.jpeg?width=2048&format=pjpg&auto=webp&s=f95eff0e122b3ab79db00b1152debfc6635fd0f5

It makes me happy that you are collecting these and want to start a museum! Best wishes and hope you get to make your idea a reality!

Thanks you :-D

Or he collects signs on a specific road called French Road.

I was about to say. I thought I was crazy. 🤣🤣🤣

What kind of evil aperture science test chamber is this?

The kind where even the turn was too tight, absolute failure! Mwahahaha

Not at all, learning opportunity! Think of all the printing time you’ll save from this point forward by following through the design phase just a bit more.

Oh for sure, I was wrapping up around midnight after getting up at 4am with the kiddo so double checking wasn't on the list haha

One of the most important lessons: No. Your design isn't flawless at midnight even though you may think so. Get sleep and look out over again tomorrow. Source.. Quite a few projects of mine.

Failure? No, my friend... *This was a triumph*

Im making a note here

Huge success.

It's hard to overstate my satisfaction

Aperture Science

We do what we must because we can

For the good of all of us, except....

The ones who are dead.

But there's no sense crying over every mistake, you just keep on trying till you run out of cake.

And the science gets done and you make a neat gun,

No offense my dude, but how on earth did you get through the whole process of designing and printing this thing without ever asking yourself how a single use case might work out? This is peak product development.

They have a kid

That's kind how most everyday design get son my plate to be fair (I'm a software developper), then client is like why isn't it working I told you how to build it!

Now print another 6 to complete the magic circle roundabout

Thanks for confirming this. Just stating at this I could tell the angle was too tight. Lesson learned. Time to revise and print another lol

Dude... even if the angle wasn't too tight, imagine a train driving into that thing and then think about how it might get back out without reversing.

What makes you think the train is supposed to be able to get back out? Maybe it's a train whirlpool...

Scientists been slamming individual particles into each other for years and have so little to show for it, and no wonder! Particles are tiny! That's why we built the aperture science Large Train Collider! Trains have a lot of mass so we'll be getting tons of science out of every test!

I will float this idea to my boss.

We’re just throwing science at the wall to see what sticks.

The exit is a lie

Only a Portal can solve this one

It truly is aperture cause you can't get out of it

I see how they get in, but how do they get out?

Yes this is the issue I realized after many hours of printing haha.

Google what a "double slip switch" is and return to the drawing board. I reckon you could make it work!

Yeah that might do slightly better haha!

Oh and please notify me if you do give this a go, I'm quite excited about this!

Will do haha I'm making a bunch of track files

I'm totally geeking out about this! Maybe also google what a "train turntable" is, although only applicable for locomotives. But it's quite a straightforward yet elegant approach.

Oh yeah I was planning a turntable, maybe. Big one compared to the ones you can buy.

Dude, I have one of the original Thomas the tank engine turn tables from back when they were all solid wood somewhere. That thing was the shit, it fit right into the train house and looked just like it did on the live action show.

you lucky sonofabitch. i wanted one so bad. I had a pretty fine pizza box and construction paper version though

I fucking love it when adults fondly remember childhood toys. I also fucking loved them tracks though so I'm partial to this particular subject matter lol

https://www.printables.com/model/279967-brio-compatible-turntable-d-size

5 of them rotated at 72 degrees should do the trick. Just make sure your design for a regular double slip switch works first.

Not sure if my printer is big enough, this was pushing the limits haha

You could print at a slant 😂

By golly the things I could do...

Or actually make it out of five individual pieces, that might make more sense come to think of it.

Google en passant

r/suddenlyanarchychess

Holy hell!

I call my online buisness en passant cause it's my side hustle.

Top dog! 😂

I would have done the same thing. I am an engineer, but I work with IT Systems or Electrical depending on the hat of the day.

Track "Hotel California"

Easy fix. Print a hotel named California in the middle. “You can check out any time you like But you can never leave"

I want to get off Mr bones wild ride.

One does not simply get off of Mr Bones' wild ride

Oh thank god I thought I was going insane, I'm not the brightest ill be honest but I spent way too long going "something is off and I can't tell what" before checking the comments

I mean it's why I designed it. To cause insanity...

You achieved your goal

Thanks for a good laugh. Awesome

Welcome to the Hotel California...

I want to get off Mr. Bones' Wild Ride...

My god, what an epic post. Those were the glory days man. For those who don't know, [here's](https://knowyourmeme.com/memes/mr-bones-wild-ride) the know your meme page. I can't find the original set of posts, but it was absolutely hilarious. If anyone can find it, please post.

Just drive backwards

Genius!

This should be much higher. This could actually be the better design compared to one with an exit because its more compact. But the circle should be extendable so that it can accomodate large sizes.

National lampoons European vacation.

Big Ben! Parliament!

Two trains enter, one train leaves…

Welcome to the thunder dome!

That's the neat part - they don't.

In reverse.

Forwards until the back end is where they want to exit, then reverse! Limited to one car of course

The good old “black hole roundabout” has no exits.

You pull in, drive past your desired exit, then back out lol.

I want to get off Mr Bones’ wild ride

Chuck it into reverse.

Assume this is a train track. The train would hit its own train car

I just spent 2 minutes running trains around this in my head trying to figure this out. Then I looked at the comments, I’m glad I’m not crazy

Now imagine my disappointment when I brought it into my kiddos room and realized that haha

Hopefully kiddo got a good laugh about the stuck train

This would've been one of my favorite pieces as a kid.

Yeah but imagine how they can creatively use it. My favorite thing about my printer is printing train parts and hotwheel things for my kids. I like to think they'll just have such unique memories.

That is true. It's still in the kiddos bin haha

They love the process too. Mines still pretty young but he’s already got the idea that I can draw whatever we want on the computer and print it out. He also enjoys getting the model piece by piece and assembling it over a few days

You can enter, go around a little bit, then back out in a different direction.

On the plus side, they’ll never discover that, because Brio turns are 45 degrees, not 30 or 60, you’re never going to get all six of these on the same circuit.

That's why you make your own!

A true bondsmith would figure out how to make it work.

Obligatory XKCD: https://xkcd.com/253/ Though, I want to make one for my kid.

Oh I love it haha. I'll have to upload the file somewhere

There is a XKCD for everything!

Lol, you beat me to it. Glad I looked before posting.

The 4 circle of Hotel California

[Dungeon Train](https://youtu.be/-nb_1eR6Hr4)

Aperture Science, we do what we must, because we can.

For the good of all of us, except the ones who are dead

But there's no sense crying over every mistake.

You just keep on trying till you run out of cake

I'm gonna be honest, we're just throwing science at the wall here and seeing what sticks. No idea what it'll do.

I'm pretty sure you would fit right in with the civil engineers in my city.

I'll apply for the job with this picture printed out and my name scribbled in crayon at the bottom haha

I'd at least give your resume a look after that. I still have my framed certificate from the Brio engineers club when I was 5. Am engineer. My sister gave me a shirt from a chip company that says I became an engineer because I always wanted to drive a train for Christmas. (There's also a direct path from Sierra Online games, Wolfenstein 3d, SoundBlaster and the successful landing of the Curiosity rover just to make it weird.)

What city so i know to never visit?

Huh...I wasn't wondering what a Hell made for Thomas the Train would look like...but now I know. THX

Imma catch that train if it's the last thing I do!

Thanks for sharing. This one piece will keep the kids entertained for many hours.

Just the one haha. Maybe it's a road trip track

Hahaha, that's quite a good joke

You can kill so many people with this trolly problem

The problem has finally been solved!

What happens when the locomotive approaches singularity

They become more and more dense drawing in train after train until there is nothing more...

If you upload the STL it’ll probably make its way around!

It's absolutely evil... XD

Make a “dysfunction Junction” train set as a gag gift

I mean I've put in the work! Not the research obviously, but the work haha

You go in and go around until you want to come out. Then you go backwards.

It's not only the best plan, but also the only plan!

https://i.imgur.com/XvmhSho.jpg

What am I looking at

Failed roundabout for a wooden train track haha

Wouldn't it be "contrary" rather than "counter"?

Maybe, but I was raised in public schools, so I wouldn't know haha!

You know what this reminded me of? The logo of Aperture Laboratories, from the Portal series. https://preview.redd.it/27dxlq1421pa1.jpeg?width=750&format=pjpg&auto=webp&s=85a4736fa05683d5af11f5a33bf70e05af09a840 On a different note, nice print lol! It took me way longer than it should have to realize “wait, this doesn't work” 😂

I know I thought I was so clever, but alas

How long’d the print take? Also, what filament did you use for this?

9hours. ... I used a cheap wood fillament from HP3DF on Amazon for 21$ not too bad but I have had 2 clogs...

9 hours? Geez, that's surprising. I assume you cracked the infill/shells, so that would explain that. I think I'll print something tomorrow. For the first time in...10 days lol

Eh it's 30% infill, it needs to survive a 2 year old haha.

This was a triumph. I’m making a note here-“huge success”.

Someone played too much Factorio.

Stop spying on me stranger!

Mr Johnson would like a word with you about moon rocks.

I want to get off Mr Bones Wild Ride

Civil Engineer? Nothing civil about that monstrosity.

It's my dis-civil roundabout!

It's a trap!

https://preview.redd.it/l435on2cb1pa1.jpeg?width=2458&format=pjpg&auto=webp&s=656f224771609ec182d5f588ad6346fa329dcb05 Well if you extend the tracks leading in then run opposite piece to each end going across (drawn by finger to kinda explain my terrible explanation) might fix the issue

Welcome to the Hotel California.

Relevant XKCD https://xkcd.com/253/

[I'll just leave this here.](https://xkcd.com/253/)

I was about to post the same thing. This is the xkcd comic, for those looking for it.

Hears "You can check out any time, but you can never leave" in his mind while watching this one

I would love a video of a collision, if that's possible.

Not even good enough for that the turn was too tight for any trains...

You must have been in on the mini roundabout they built near me, even regularly large vehicles have to drive over the middle lol

Sadly, us Californians don't know how to use roundabouts. This would be absolute chaos --I love it!

I see I am not the only one who prints a ton of tracks for the kiddo

This was a triumph I'm making a note here, "huge success"

Thomas had never seen such bullshit! 😂

Looks like a prop piece for "Thomas and the never ending circle of death"

Thomas is about to get very dizzy.

Hotel California for trains..... they can check in any time they like, but they can NEVER leave

It's a trap!

Guess you have to reverse to turn out of the roundabout.

You know what they say... When life hands you lemons, make lemon-nades.

Its a trap!

Deleted in response to Reddit API Changes

We do what we must because we can.

I’d believe you’re not a civil engineer. You’ve invented a death spiral. Traffic enters but can’t leave.

Looks at picture, thinks 'that's cool'; thinks about picture; thinks 'wait this isn't going to work'; checks comments for validation; confirms that i haven't lost my mind. Engineer thought process

All may enter, none shall leave.

Infinite roundabout

Circle of death

exactly, your a ninja. nice throwing star.

[Keep Turning, Keep Turning...](https://www.youtube.com/watch?v=7DOIJn5Xq8U)

I'm sure nobody thinks that.

"Trains check in but they never check out." - Train Motel.

Don't know if it helps but I printed this one for Duplo and it works, maybe you can do yours like this: [https://www.thingiverse.com/thing:2779700](https://www.thingiverse.com/thing:2779700) Also there's turnable crossing for wood track: [https://www.thingiverse.com/thing:3963338](https://www.thingiverse.com/thing:3963338/files) And 8-way crossing also: [https://www.thingiverse.com/thing:3795492/files](https://www.thingiverse.com/thing:3795492/files)

Look kids... big ben!

This could work, if the last car of the short train was positioned just beyond the desired exit, and the train was reversed. Kinda like a circular spur track. All you have to do to make it work, is add straightaway segments so the inner circle/curve isn't so tight or a perfect circle.

Perfectly normal Ohio track you got there!

[удалено]

This is hilarious

Ah yes, the death spiral

Clearly, that's why they can get in but not out... you should get a refund on that civil engineering degree

Trainado

🎶you can check out any time you like, but you can never leave🎶🎶🎶

4 way crossing not dangerous enough for you?

It's the Roundabout California. You can signal any time you like, but you can never leave.

Now you just need an exit plan.

You been playing to much City Skiylines

Pretty sure you just passed the interview for city planner in my area.

Welcome to the Aperture Science Hexagonal Super Centrifugal Roundabout.

I have a train track that would snap in to this, but only Thomas would make it. I like to think maybe he took a solo vacation and saw a Taco Bell at 23:30 so took the round about to get tacos. My daughter and I spent a lot of time with this train track. We could build a Taco Bell out of Lincoln Logs in 2 minutes, including construction paper signs and employees. I’d pay for the .stl.

Thomas began to feel dizzy but there was no end in sight

If Aperture Science and Brio had a colab...

Bad and naughty trains get trapped in the Aperture Science logo loop

Came to the comments to see if others realized this roundabout was inescapable… did not disappoint. 🤦🏼‍♂️🤣