How rollercoaster anti-rollbacks (ARB) work to keep you safe

When rides go up the lift they are being carried be a chain dog. What happens if the chain dog breaks? It’s happened to me working on a ride, I snapped clean in half. What happens if the chain breaks? We don’t want the train to go backwards because it will catastrophically collide with the train in the station, and injure people in both trains. So devices called Ani-rollbacks or ARB for short, were installed to make the lift a one way trip.
Safety ratchet dog arb 00:01
Toothed rail 03:44
B&M sprag test 06:50
ARB clunk 12:00
ARB Cam 20:40
Space Mountain 28:50
Water rides 37:00
Inverted ARB 40:30
ARB silencer 42:40
Only for lifts 50:30
ARB funny sound 56:20
ThemeParkHD
/ @themeparkhd
Space mountain video • Space Mountain - Night...

[@jpgiles1725]

23:50 -24:27 That whole bit killed me 😂 Honestly, I think I prefer the cardboard cutouts. It helps me understand how it works better. It just clicks in my brain.

[@FelInferno]

I used to work on a 1920s wooden rollercoaster with a brakeman, (Scenic Railway) it had somewhat conventional ARBs albeit much simpler than B&M ratchets etc. But it previously had another system. No up stops or side wheels, just flanged steel wheels like a train, running on a small steel rail. On the lift hill and other uphill sections, the wood supporting the rails was wider out to the side of the rails and the trains basically had spring loaded spikes that would dig into the wood if the train were to loose momentum!

[@ryantheridemechanic]

That’s interesting!

[@soccerndog3785]

I’ve always been knowledgeable on roller coasters and stuff like this. I just enjoy watching your channel to improve my own knowledge.

[@litz13]

The anti rollback cams are old technology, first used in safety brakes on elevators. Very very effective as the more gravity pulls on the thing the more the cams bite in place.

[@Stuntman707]

The B&M system sounds really good being able to monitor the anti rollback operation on every dispatch. At Europa Park, the chain broke on their GCI wooden coaster so as rare as it is, it can happen. Apologies if you’ve already explained but it would be great to understand more in detail how the launch abort / roll back works on launch coasters. Once I saw the mechanics walking out the launch track with a can of oil and kicking the stuck fins back up.

[@nuttyfruitloaf]

22:19 yessssss 🗣🔔 thank you!

[@TripleTSingt]

when I was working at Black Mamba I learned about an interesting thing that can happen with the ARB "dogs": There is a little ramp at the entrance to the station that pushes the dog down (since its an Invert, they have to be pushed up into the ARB teeth with a spring) and a sensor after it, checking if it came back up. And when it's cold, they sometimes don't come up fast enough. So you have to reverse the whole train into the transfer track to try that again, since it won't let you dispatch a train with that fault active. And if you have two trains on it, you had to reverse both trains, one after the other. We ended up switching the trains multiple times, but it was so cold, it kept happening.

[@jvanhoozen21]

Arrow suspended coasters have unique anti rollbacks too! I worked on one and the fixed part or the "tooth" was actually on the train and the moving cam part or the "dog" was placed upside-down the entire length up the lift. I believe Arrow did this as a "fail safe" since no parts required springs but gravity would pull the dogs down on the top side. Obviously outdated since it was now wayyyy more than 4 moving dogs with the dampeners that would need to be checked and replaced (maybe 100 +) Our maintenance team would go and have two push up each one as they went up the lift each morning to check them all.

[@ryantheridemechanic]

Must have made good sense at the time.

[@porcelainthunder2213]

The Arrow ones sound the best! Your props are amazing.

[@ryantheridemechanic]

Thank you

[@porcelainthunder2213]

@@ryantheridemechanichave you seen the wooden side-cam variety on Leap the Dips. Just boards nailed onto the lift hill. Hard to think they’d stop anything

[@ryantheridemechanic]

@@porcelainthunder2213 wedges like that have a surprising amount of hold. We supported 20ton tractors sections with a simple 2x4. They had no trouble holding that weight.

[@SkeledroMan]

i know Gerstlauer uses cams on the track for their family coasters, like Firechaser express and Pegase express. Must be tougher on maintenance though.

[@m00gal]

I did a track walk on the Big Dipper at Blackpool Pleasure Beach a few years back (a coaster that's over 100 years old now) and they explained about the anti-rollbacks on the tops of the hills - they said that if the train stopped there then they could get it going again by having a load of staff give it a shove, whereas if it rolled back down the hill you were basically going to have to get a crane or similar to winch it out, which is a huge inconvenience in a park like that where everything is so densely packed in. At the same park there's some cool old anti-rollbacks on the Ghost Train - more similar to the paddle sort you see on a log flume. You can see (and hear!) them very clearly in a POV.

[@ryantheridemechanic]

Cool

[@jcwolf8311]

The laugh track got me so good 🤣🤣🤣

[@dindog22]

you just answered my question. I have been wondering for years what causes the huge clunking noise on Valravn when it goes through its first inversion. I decided that it had to be whatever massive chain dog they were using

[@ryantheridemechanic]

Cool! Everything acts in unison when you take force away.

[@MythicHellebore]

Cardboard arts and crafts with Ryan is fun. I enjoy the visual aids. Last week I went from hyper fast Skyrush lift to Wildcats revenge and thought the chain dang near stopped😅

[@ryantheridemechanic]

Quite a speed difference

[@allisonreamor5027]

Oh how do I love seeing these videos posted! They are so educational yet entertaining. I always look forward to them. Speaking of that, when is the Intamin Freefall video coming out? I am really looking forward to that one since they are so unique.

[@ryantheridemechanic]

It’s in the works but a ways out

[@jackschissler255]

You should talk about the B&M Dive coasters how they use (I think) the same ARB and chain in the down side of the track to hold the train before letting it go over the edge. I always thought they used an extremely powerful magnet to hold that train over the edge but I heard it’s just the ARB doing double duty.

[@ryantheridemechanic]

Yea those are interesting. I’ve never worked with one but I understand the basics. Need to get more info first. They use 4ARB 2 chain dogs and one drop dog that’s basically a chain dog facing forward instead of backwards.

[@jackschissler255]

What was the reason why Arrow lift hills were loud? You can always tell an Arrow from anyone but some like Magnum XL200 were super loud compared to their others and I notice RMC had loud ones but Steel Vengeance @CP really turned up the lift volume on that one.

[@ryantheridemechanic]

@@jackschissler255 big heavy anti-rollback dogs. That’s it. Just big stuff making big noise.

[@jacobliford]

Thanks for posting all this info. I’ve always been fascinated by the inner workings of rides. These videos scratch that itch. Do you have anything talking about drop type rides?

[@ryantheridemechanic]

Yes I do kzbin.info/www/bejne/oHnZpGhseJqNi6csi=v7zLqICbsU0lBGR5

[@ellexking9136]

This is a Great video Ryan!! Very Interesting on how the Cams work. That got my attention. Question about the Anti-Rollback Teeth on a couple of other Rollercoasters built by PTC. Blue Streak at Cedar Point has one row of Anti-Rollback Teeth on hills throughout the course, And Comet at Great Escape has two rows of Anti-Rollback Teeth on hills throughout the course. And both of those Coasters operate with 3 Bench 4 Car PTC Trains. The two mentioned Rollercoasters are much older, But I've always been curious about the difference of the Anti-Rollback Teeth system on them. Thanks.

[@ryantheridemechanic]

That’s a real tough one. I honestly don’t know the madness behind those decisions. From a practical point of view. If you use two sets of toothed rails, the coach is symmetrical making fabrication easier. If you only use one rail., then the coach is no longer symmetrical becomes as a-symmetrical. Also, when using two rails, it holds the train evenly compared to one rail, which will want the train to lean towards one side or the other. Just my thoughts.

[@ellexking9136]

@@ryantheridemechanic Thanks for your feedback Ryan. Also The Beast, and Racer at Kings Island also has double sets of Anti-Rollback Teeth along the circuit. I've always thought maybe it's because of the number of Cars for The Trains, of course means more weight. The Beast has 6 Car Trains, and Racer has 5.

[@MLDesigns]

Haven’t finished the video so you may have answered it- but with the cam-ARB method , how often does the fin have to be replaced from those cam teeth biting into it? Or does it not damage the fin all that much?

[@ryantheridemechanic]

Rail is fine. Every year on the teeth.

[@markvolpe2305]

I remember back in the late 90's early 00's on Darien Lake's Arrow looper, Viper, the park had put leather strips on the anti rollback teeth to dampen the noise it made, it only lasted a couple of seasons before they removed them. Also, at the same park, the SLC Mind Eraser, whenever the train engaged the lift hill and heads up the lift about a quarter away, it always makes a moaning or a cow mooing sound, what is that from?

[@ryantheridemechanic]

I would assume if the chain liner was bad it would have been fixed after the first year or two. Could be the ARB rail I would venture that the rail is out of center with the track if that’s the case. Could just be harmonics with the removable hand rails on the side as well.

[@andrewleonard3623]

I’m suprised there’s no lock to keep the ARB’s from making that noise during the 0G moments.

[@Ravaxr]

A lock would be a bad idea on ARBs, and springs to hold them down would wear out and be more expensive to maintain. But I could see putting a pad on the rest position, so the ARB makes more of a soft thunk than a hard clack. That said, I don't think it is big enough of an issue to worry about once you know what it is. I actually like to hear that clack, because it means there is definitely good airtime there. Also holy hecc Rocky Mountain needs to add some pads in general. Their ARBs are deafening.

[@ryantheridemechanic]

@@Ravaxr and to place a pad on the arb you would have to thicken the dog itself and increase the height of the toothed rail. So not an easy retrofit unless they are already thick enough.

[@exhibit13productions]

Are the cardboard ARB teeth and dog 1:1 scale? I always wondered how big they actually are. I find that a lot of coaster equipment is deceiving in that it looks small but is actually quite large up close.

[@ryantheridemechanic]

For the dog and tooth rail yes they are 1:1. For the cam assembly i made it about twice the size of an actual cam setup

[@NewEnglandModz]

Is there an advantage to using cams as replacements for booster wheels in the Space Mountain station? Booster wheels seem simpler.

[@ryantheridemechanic]

I’m guessing, it was probably a SPACE…. problem…… maybe. Using the cams they were able to put motion in a large area. Only about 8 inches thick overall. Booster motors typically need a lot of room underneath the ride for working. Disney is also very big on keeping sound down in which case booster drive motors make a lot of noise. And for booster drives, you typically need a pair of them to move the train forward but because of the gap in the brake fin, you need to put four booster motors where the ride needs to push, and there is a gap in the fin.

[@sumguy8]

You're said "acrost" and "across" in the same paragraph. I feel like you are messing with me! lmao! Great video

[@dindog22]

you need to build an entire cardboard roller coaster

[@ryantheridemechanic]

Ha! That would be funny.

[@NewEnglandModz]

Do rides that use drive tires use any anti rollback devices? Like Hulk, for example? Same question for lsm/lim hill launches, like Mummy. If the lsm/lims are used to slow the train back down, do you know how the block zones would work for Mummy (in Orlando) specifically? I would have thought that the spin track would be its own block, allowing the bug room to go into it as soon as the train on the spin track advances up the hill. But if the launch hill can slow the train down back into the spin track, is that one big block zone (spin track and hill)?

[@ryantheridemechanic]

So for most rides that use LSM technology, they will typically just allow the train to slide back down the left hill and stop at the bottom. The base would be the entry to the block. For rides like the Hulk, booster will act as anti-rollback devices, so they don’t have to worry about adding mechanical devices on top of that. I would imagine on the Hulk you would have the lift Hill all the way through the inversion is one block, and then you could probably start advancing the next train. Once it clears the inversion, but you cannot start the speed process until the train front clears. The block breaks. So I’m guessing somewhere after that first inversion there’s proximity sensor to say it has left the area probably two sensors to count the train out of the block.

[@Bigbluespoon]

So with the b&m example that would mean coaches 2, 4,6 and then either 7 or 8? If it’s running 4

[@ryantheridemechanic]

Yea basically every other coach. In general the pilot coach has no attachments due to the pilot pin installation.

[@spinba11]

I thought anti roll backs were simple, judging by the video length obviously not

[@ryantheridemechanic]

They are I just talk long