Millennium Force Cable Issue

CPFan420 said:
The train has a pin that drops down when the magnet that holds it up is released by an electrical current.

I don't think that's the case... unless you're thinking of Dragster (Dave would know better on that ride). The end of the catch car is just a simple horizontal pin like any on a traditional chain. The dog under the fourth the car of the train works like any traditional chain dog. In this case, when the catch car slides under it, it's like a chain sliding under the chain dog, and when the train moves past it, off it goes.

From the photos I've seen, it would appear the end of the catch car track is open-ended. Given that, it's not surprising that it would be hanging out, flapping in the breeze. It also offers hope that it's not seriously damaged.

The cable break, I think in 2001, managed to mangle the catch car's track pretty badly, cutting through to the anti-rollback notches in it. I know someone had photos of it, but I can't remember where. They still managed to execute a quick turn around for the fixes.

Thanks, Jeff, I was alluding to that post but was too lazy to find it; this thread is growing fast.

On Dragster, there is a spring-loaded pin which is magnetically lowered into position into the catchwagon. The train is dropped backward until the pin jams against the back of the catchwagon, then the magnet is released. The pin remains jammed into place until the train overruns the catchwagon at the end of the launch track, at which point you can hear the pin swing back up and hit the bottom of the train. They do this on Dragster because if the train rolls back, they absolutely DO NOT want the pin to hit the catchcar; that would cause Very Bad Things to happen.

On Millennium Force, a rollback would be a Very Bad Thing, so as Jeff just said and as I noted in my earlier post, it uses a more or less conventional chain clutch, which can only roll in one direction over the catchwagon: the train can go forward of the catchwagon, and the catchwagon can go backward of the train, but the other combinations won't happen. This is in addition to the anti-rollback mechanism, which, as others have mentioned makes a horrible racket if the train moves slowly enough for the anti-rollback dogs to engage.

--Dave Althoff, Jr.

If nothing else, this was a bit of a learning session for me on how the lift system works.

Anyway, hopefully they make some progress and we find out how long the fix could potentially take later today.

I was under the impression they were similar but you are correct I can imagine how when the catch car slides under the train in "clicks" into place when it reaches a certain point.

I was looking at the photos this morning, and I think I know why the catch car didn't fall to the ground in a heap. If you look at http://img40.imageshack.us/img40/7980/p5280014n.jpg you can see that the cable used to pull the catch car up is still attached. That's also the picture where it looks like the end of the catch car track is open. I think it failed exactly as expected.

I swear Rideman is like our Professor for our Ride Mechanics 101 class :)

Maybe it's me but why do people get so upset over MF being down? CP has tons of other coasters and tons more to do. Maybe it's because it is far from my fav steel (1 big hill-all speed no substance) but if I had to wait on a long line, I'd rather wait on Mav.

I am sure MF will be fixed soon enough, especially since CM is next week. Trust me, the last thing CP wants to hear is a bunch of enthuiasses carrying on on why MF is closed. Park Ops had this "fun" in 2007-or was it '06? MF was down but they got it up and running in time for some PM ERT.

As for me, I'll be on Raptor :)

Jo

^Its becuase MF is one of "the rides" people want to ride at CP, and one that usually has long lines the whole day making the ERT something a lot of people want. For a lot of people, its their favorite ride, how would you feel if something happened to Raptor and it wasnt open for CM?

Yes Mortimer, I think you are right. The catch car flipped over itself because the haul rope stopped it from falling to the ground after the return rope broke.

For people making their first, and maybe only trip for years to CP, I'd be fairly upset to have to miss one of their biggest and best coasters, which I have dreamed of riding since the day it opened years ago. It's not like I'm missing a simple mine ride coaster, or Corckscrew or Wicked Twister which are duplicated all around the country. It makes sense why many of us making our first trip to CP next week are sweating the fact one of the top rides may not be open to try. All I want is one ride, as who knows how long till I ever come back to the park.

From watching the Funcam this morning it looks like they have either got the catch wagon back in the track or removed it alltogether.

This might be a dumb question - but why would they even allow the catchcar to come out of the groove on the downhill slope? Wouldn't it be possible that if the cable broke - the catchcar will come out (like it did here) and carry with the train through some of the track and maybe even cause serious damage or derailment? That just seems like an awfully huge object to be able to come loose right on the track.

They are worried about people bringing cameras or other things on the trains.. that is very small compared to a huge catchcar like this.

I don't think the catch car traveling with the train along the track is an issue. Mainly because the train at the top of the hill would be moving quicker than the catch car and therefore becomes disengaged from it and moves down the hill faster than the catch car could.

I'm guessing here because we don't have any solid information but I think the train was probably at the bottom of the hill and starting to move into the overbank by the time the catch car fell out of the bottom of the channel.

Ryan

^How so? The train and catchcar are moving at the same velocity at the crest, as the train is being pulled by the catchcar, and we all know how gravity works (which falls faster, a 100 lb weight or a penny)...

But at the same time, as Rideman said, the catchcar can travel backward relative to the train, so even if it did reach the end of the channel the train could just roll right over it.

^My thinking behind it and again I don't know anything more than anyone else, is that the cable engaged and started to slow down the catch car before the cable broke. The only reason why I say this is because if you watch this video:
http://www.youtube.com/watch?v=sHFi2OtqJlw

Starting at 0:24 you will see that when the train just starts to roll over the top the catch car starts to slide out from under it. (watching this happen is one of my favorite parts of riding in the front seat). So, even if it was slowed down a little bit that would give the train enough of a head start to beat the catch car to the end. I would also go as far as to say that maybe the friction coefficients of the train wheels versus the catch car wheels may be in favor of the train beating the catch car down.

Again this is purely a guess.... But I sure do love to guess haha

Ryan

At what point does the ride computer become 'aware' that something is not right in this case?

I've been following this thread since yesterday, and I'm guessing that the return cable broke, the catchcar slid out of its channel, and got stuck and flipped over itself due to the fact that it was still attached to the other cable.

My only question is why they didn't have a "stopper" at the end of the channel, where only the cable could fit through it, to prevent something like this from happening.

^ They may not have put a "stopper" at the end because the catch car could of had enough energy to just rip right through it and cause more damage. Also, it then could have put to much tension on the lift cable and snapped it as well.

Again, just speculation.

Ryan

Dvo said:
^How so? The train and catchcar are moving at the same velocity at the crest, as the train is being pulled by the catchcar, and we all know how gravity works (which falls faster, a 100 lb weight or a penny)...

They both fall at the same rate of speed. Its air resistance that causes the penny to hit the ground after the weight

If air resistance is the only factor, wouldn't the larger 100 lb weight take longer to fall?

I'm sure the computer can detect the failure in all kinds of places, given the number of prox switches they put on that ride. The tension on the counterweight pulleys would be gone (I know there are switches on it, just not what they're supposed to detect), the cable on the drum would not be there, the switches in the station would note the lack of the catch car, etc. I bet the comprooder would get very confused.

It's interesting to bring up the "correct" failure pattern, and honestly, I'm not sure if it was given all that much thought. I agree that allowing the thing to just slide out on the downside of the drop seems... random. At the other end, the catch car track goes the length of the load station, then diverts under the transfer (see these pieces), which is useless because it assumes that the the return cable is the one that broke. When it was the hauling cable back in 2001, the return cable just jammed it and the catch car got jammed up at the front of the station.