Let's talk about Rollbacks, Sleds and Cables...

I have several questions about Rollbacks, Cables, and Sleds (Oh my!).

1. When the train rolls backwards, does it collide with the stationary sled that has just launched the train, or does it "hide" somewhere? Or would the train hitting it not really cause that much of a problem?

2. Can the ride ops just re-dispatch the train immediatley after the roll back, or do they need some sort of maintainence check up?

3. Can the cable attatched to the sled, snap, similar to what happened on Millennium Force?

4. Is the cable attatched to the sled a continous loop of cable, or just one long section?

and finally,

5. When the train rolls back, what stops the train immediately following the launch track, where the ride starts in front of the station? Friction wheels, or drop down brakes, like on the launch?

Thanks for any insight you can provide!
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Jes
Jes's Roller Coasters DJ Jes
Six Flags Worlds Of Adventure 2002 Ride-Ops Crew! Have fun trying to find me!

1) There are brakes on the launch track to stop the train in case of a roll back.

2)I dont think they redispatch the trains immediatly, But i am pretty sure you will get a re-ride in case of a roll back.

3)The cable can snap. This isnt very likely. But anything can happen.

4) The cables just goes around and around. It is in a loop

5)Same as 1 i think

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- Dennis
NYC Subways, The next best thing to riding roller coasters.

#1) Good question, but I think the entire launch cable is a big circuit, so I dont think it could happen.

#2) I think there would be a brief check, but they wouldnt shut it down. I know Xcelerator and Hypersonic (I believe) Rolls back occasionally, because they miscalculated the weight of the train and the force needed to launch it.

#3) Yes, and boy I wouldnt wanna be NEAR that thing if it broke.... I bet it could cut you in half!

#4) A big loop of cable

#5) Those magnetic fins you see 'drop' down on the launch track for Xcelerator are braking fins in case of a rollback, these stop the train before colliding with another train or rolling back into the station.

Hope I helped out!

1. It's hard to say, I've asked the same question, only to get idiotic answers. Big D, try re- reading Zero_G's post.

2. I believe Xcelerator unloads for an adjustment. Also, it probably causes an E-stop for saftey reasons.

3.Yes, **** happens. While very unlikely, there is always a chance of it happening. XC has two drive cables instead of MF's one.

4. MF uses a totaly different gauge cable for each side of the lift. Xcelerator uses two drive and one return cables. So it has 3 cables attached to both the drum and the sled.

5. The train will be going about 1 MPH backwards during rollbacks for a good part of the launch. The friction wheel will easily be able to stop that.

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Remember, "Being fat can even ruin a romantic cruise"

Xcelerator has to do a few test runs after a rollback. I don't think maintanance comes, but I'm not sure. The riders get a reride. It may be different on Dragster though.

Now I know if the sled were to slide backwards under the train it would not catch on the lift dogs. I wonder if the same would apply if the train rolled back over the sled such as in this case. When they transfer off trains on Millennium Force the sled is still in the station when they back it up (the sled is moved up a hair though) and the trains just slide backwards over the sled.

I'm not sure how the lift dogs work exactly (Like how they know when it's time to attach to the sled), but they do move up and down to either engage the sled or not. I've always assumed they were designed to engage only when the left sled is trying to push the train forward. So if the train were to slide back over the sled they just might not engage and the train would skip right over.

Another thing to consider, if a rollback were to occur, it would be a while till the train made it back down the tophat/hill. This gives the sled some time to retract back and by then the train may be moving slow enough to avoid any damage.

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Wow, a new ride is being built.

1: (Big D: You didn't answer his question, he knows the train will be stopped.) I've not seen the cousin operate, but it appears from watching the video on Twisted Rails that the drum reverses direction almost immeidately when the launch is complete. I don't doubt that it's already headed back downtrack as soon as the train is released.

2: Xcelerator's procedure is apparently to launch an empty train after a rollback, prior to loading passengers again.

3: Any cable can break, but I don't think they'll let it get to the point the MF cable did. It's certainly easier to change, seeing as how you don't have to loop it 310 feet in the air.

4: The cable is certainly not a continuous circuit if it's built like Xcelerator. In fact, it's the same setup as Millennium Force with the drum.

5: Again, assuming they calculated as they did on Xcelerator, the train will crawl by the time it rolls back to the station. Keith "Badnitrus" McVeen got a rollback on Xcelerator and he said it took forever. I think it's safe to assume that the kicker wheels will stop it.

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Jeff
Webmaster/GTTP - Sillynonsense.com Rave Cam 1/18
DELETED!

On Millennium Force, the lift dogs on the train are exactly the same as the chain clutches used on any other coaster. They are basically gravity-loaded ratchet teeth. If the train moves forward relative to the lift sled, the dogs disengage, but backwards they will engage. That way, if the sled goes backwards, the train disengages. Remember that normally when the lift sled is brought back down into the station it is not brought down far enough to engage the train until the train is dispatched, at which point the sled is backed up under the train, then pulls forward to hoist the train up the hill.

The patent drawing for the Intamin launch mechanism shows a cable drum with three winding paths on it. The two pulling cables wind on the outer edges of the drum, and the return cable plays out from the center of the drum. Consequently, the winding drum is used to pull the launch sled in both directions, just as on the Millennium Force lift.

I have not yet learned how the launch sled will connect with the Dragster train, but it appears to me that in the event of a rollback, the train will end up pushing the launch sled back to the starting point. That may be the mechanical stop that prevents the train from overshooting the launch during a rollback and colliding with a train in the staging area downtrack of the load station...short of a catastrophic failure, it will not be possible for the train to proceed backward past the start of the launch track even if the rollback brakes should fail.

Unfortunately the patent in question is a European patent and my German is a little rusty... :)

--Dave Althoff, Jr.

My Mistake. I misread the question. SteelMonsters..What was so idiotic about that??...I made a mistake. Thanks for that idiotic comment though.

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- Dennis
NYC Subways, The next best thing to riding roller coasters.

What I want to know is that according to Jeff, there will be two trains in the "ready" position (that is, after load).

What happens if the first rolls back? They would have to push all the trains back through the station. The one in the ready, and the two that are being loaded.

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"I can't make a movie or write a song either, but that doesn't mean I'm not entitled to think they suck."
-Jeff

The only thing worse than people who make grammar mistakes are the people who have to point it out every ****ing time.

No, they wouldn't have to push everything back. The short-shot train would only go back as far as the start of the launch track (a trainlength beyond the staging brake) to be re-launched.

Remember, on Xcelerator, the launch starts in the station. On Dragster, the launch is at least two brakes downtrack of the station.

--Dave Althoff, Jr.

Thats what I was thinking Mr. Althoff, regarding the sled and rollbacks. Sure, you've got the drop down brake fins, but if I know anything about today's coasters, it's that they always have a back up plan in case the regular method doesn't operate correctly.

Most likely, the train in the staging area will not advance forward until the train currently being launch clears the top-hat element, so there should be no concern of having to push the train back. Additionally, it appears as though there are drive tires to advance trains before the staging track. As is the case in most coasters, those motors can push the train forward or backward (If nessecessary).
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Jes
Jes's Roller Coasters DJ Jes
Six Flags Worlds Of Adventure 2002 Ride-Ops Crew! Have fun trying to find me!

While we're on the subject, has anyone been able to see if the cables travel in an oval, or in a figure eight style, as shown on a site linked to here? The point of crossover being after the cables have left the track, but before they reach the drum.

Also, is it safe to assume betewwn the drum and turbine system there's a clutch? That seems like it'd be the easiest way to slow and reverse the cables.

Now if I could only get a look inside the turbine system I'd be set.

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VertiGo rides: 32
2002 Raptor Crew
"Hey, Cool. My voice is on the lift"

The patent shows the two hoisting ropes diverge and wind onto opposite ends of the drum, with the return rope unwinding from the center of the drum, so no rope crosses any other rope.

I hope there is a clutch in there... :) But really, with hydraulic motors it wouldn't be necessary...to cut the power, just open a dump valve...

--Dave Althoff, Jr.

I don't know about engaging the sled while in a rollback. Wouldn't a sudden engagement at somewhere around 100mph really stress the dog on the train? I agree though, that would be a good redundent safety system if it works that way. In the video on WEWS this week, Monty Jasper mentioned that the train goes over a limit switch at the top of the tower. Maybe the sled waits until the train crests the hill, and then quickly goes back to the launch point to launch the next train.

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Florida may have Disneyworld and Key West,
but Ohio has Cedar Point and Put-In-Bay.
It's great to live in Ohio!

Rideman, do you have a link to this patent? I've searched online, thus far with no luck.

With regards to the cables crossing, I was actually thinking of the side view, not from the top down perspective. Do the cables on the sled travel to the bottom of the drum, with the return cable heading towards the top, or is it the other way around. I don't know why one way would be better than the other.

I was thinking about the turbines, and I found a few picutres that are probably similar to the actual design. The intake port is on the long the side of the 'rectangular boxes', with the larger exhaust ports on the furthest end. Those being the very large hoses seen on Xcelerator. The design of the blades forces the hydraulic fluid towards the exhaust ports. The blades are one end of a shaft, with the other end having a relatively small gear on it. There's ten such assemblies mounted on each side of the drum. The small gears turn a larger gear, which in turn, rotates the drum. At least that's how I see it.

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VertiGo rides: 32
2002 Raptor Crew
"Hey, Cool. My voice is on the lift"

Here's a link to espacenet.com.

The tricks to finding that are (a) to know that it is a European patent not a US patent; (b) to know that the name you are looking for is "Spieldeiner"; and (c) to stay late in the Monday Night #roller-coaster chat where one of the other participants provided me with the link. :)

--Dave Althoff, Jr.

Rideman- what network is the #roller-coaster chat on?

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- John
Support Rob in theGreat DDR Challenge!

Monday night chat:
When: Monday night, starting about 8pm Eastern US
Protocol: IRC
Network: irc.starchat.net
Channel: #roller-coaster
Operators: Jerry Dorf and "Coasterville" Dave Bowers

--Dave Althoff, Jr.

I'll be sure to stop by next week, then. :)

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- John
Support Rob in theGreat DDR Challenge!