that clicky-clack noise going up the first hill

I've always wondered about the wisdom of putting the anti-rollback dog on Magnum's car 5 instead of car 6. If car 6 detaches from the rest of the train on the way up for some reason, the riders on car 6 would not have a good day.

Rollback on Magnum!! :)

^^ - I was wondering the same thing. That was part of the reason I expected them to be on every car.

It's beyond hilarious how some people actually think, esp. newbies to the park, that when the chain lift pulls up and the chain dogs make that clanking sound, that it's going to fall apart:)

Pete said:
I've always wondered about the wisdom of putting the anti-rollback dog on Magnum's car 5 instead of car 6. If car 6 detaches from the rest of the train on the way up for some reason, the riders on car 6 would not have a good day.

To some extent that happened on Disneyland's Big Thunder Mountain Railroad in I believe '99. The lead car (the engine) doesn't have (or didn't have I should say) anti-rollbacks. It broke free from the train and since it didn't have the anti-rollbacks to keep it in place it rolled back and collided with the train.

It seems like every car should have anti-rollbacks for the above reasons. And it also seems like it wouldn't really cost too much or affect the ride too much. What's stopping parks from installing them on every car?

hey now....i was not complaining. if i was, i would not be on here 2, 3 hours a day.

Hmmm,

Theoretically, would the last car on Magnum have enough momentum coming back down to both take the turn and go up the little dip back into the station? If so, I wonder how far up the lift it would have to be.

Where's my calculator!

^I'd be more worried about that little 90 degree turn at the bottom of the lift snapping people's necks if a train took it at 40 or 50 MPH.

Honestly though, if a train is going to come apart on Magnum, it's going to happen in a higher stress area like the bunny hops in which case anti-rollbacks aren't going to do jack squat.

Also, if you notice, between each car, there is not only the coach coupling (hitch), but also a chain. While I have my doubts as to the effectiveness of a chain if the train were to separate on the course (even if it held the train "together," you'd still probably get cars slamming into each other at the brakes), I do believe it would prevent the last car from rolling back down the lift if it were to happen on the lift.

I get what you're saying, but I don't really see it being a big design flaw or something.

I question the use of air pressure to close brakes as well as leaving the last car without an antirollback. I wouldn't do it the way Arrow did it for either case if I was in the position to have designed the ride. Then again the ride was built when safety wasn't as big of a deal. Both are designed redundantly, although the brakes using air pressure to close may have contributed to the incident. If any connection between cars is going to break, it's going to be further up in the train where there is more stress.

Some people hate that sound,But I love it.Maybe when I was a kid it scared me a little.But that just brings back memories when coasters made that noise.I still love the fact that we have other ways for stopping rollbacks that aren't as noisy.But I'd like to see that design stay on some coasters in the future.Gives it that retro feeling.

^^ - unless Arrow did it completely backward from everything else, the brakes are opened by air pressure. They are closed by a spring. So, the default is closed (on) and the system has to actively open the brake.

We need to get Rideman in here to explain why the Arrow braking system (it is opposite most) is still perfectly safe. They DO require the air to close, but they are still failsafe I believe because there are tanks of stored air so trains can still be stopped even if the compressor were to fail. I'm not sure what happens if an air hose breaks. Maybe he could explain that.

On Magnum, in the event of "low air pressure," you can't dispatch any trains. But if there's one out on the course, it will still stop.

You don't have to take my word for it. Rideman addressed that fact on his wall of shame where someone put too long of a chain on an Arrow.

The brakes basically use an air blatter that sits between the brake caliper and a back plate. The same is done for the other side. When air pressure is applied, the blatter expands and pushes against the back plate and the caliper. The backplate is fixed so the calipers close. When air pressure is released, a spring returns the calipers to their open position.

How air is applied to the brakes is rather complex, but it's designed to be safe even though it rests on a "flawed" concept.

*** Edited 8/13/2007 12:47:44 AM UTC by Jump to Conclusions***

Jugga and those intrested.... A good read on the subject is the thread about Magnum's accident earlier in the season. About halfway down Dave (RideMan) goes into detail about the brakes and the spring-release type of brakes on Arrow coasters.

Matt, since you worked on Magnum... arn't trains on Arrow coasters parked on the lift hill at night or a bar is put across the rail where the trains are park in case the air tank leaks?

*** Edited 8/13/2007 3:50:57 AM UTC by Andrew***

Our closing procedure on Magnum called for one train to be transferred off where it was chained and also there was little stoppers that we flipped up in front of the front wheels. Another train was left in the ready brakes behind the station. This one was also chained. The third one is parked in the safety brakes outside the third tunnel. It wasn't procedure to chain this one although there was a chain up there if I remember (probably for evacs). The station is left empty.

When we would arrive in the morning, the train that was behind the station would be in the station and the one that was outside the third tunnel would be in the readies behind the station. It's possible that nightly maintenance procedure called for the air in station brakes to be bled out, then the air int he ready brakes to be bled out (allowing the train to roll forward toward the station, and then the air in the safeties to be bled out.

I certainly don't want to make any accusations because I was never there at 2am or whatever to see for myself, but I wonder if this was really being done every night since Dave said it's standard procedure to do it daily on Arrow rides. Whenever a train wasn't parking in the station properly or whenever we were getting safety brake overspeeds, maintenance would often bleed the brakes at that point. There was often quite a bit of water that would come out - like multiple cups, not just a few drops.

What I'm getting at is I wonder if this could be the reason why they blamed "excessive moisture" for the bumping incident earlier this year. Excessive moisture caused by not bleeding the brakes like they were supposed to, rather than so much by the rain occurring at the time. It was certainly raining that day, but I've personally let Magnum run through much heavier rain all without incident.

I don't really know if the water in the lines/tanks hurts brake performance or just has the possibility of corroding the tanks. Maybe someone else could have a better answer on that one.

^ - that sounds about right for a management decision. They hear moisture, see that it was raining then and determine that the rain must be the moisture maintenance was talking about.

Sadly, this kind of decision making skill is not limited to just the amusement industry.

That's a very interesting point. If that was the case, it's a good thing that it rained that day. Otherwise they'd really have some problems on their hands.

Water in the air lines will corrode the receivers (tanks) valves, and lines. It can cause operational problems such as causing parts of the system to "go solid" where the water filled sections don't operate correctly.

The water come from humidity. When the air is compressed the temperature rises increasing the capacity of the air per volume to hold water but the amount of actual water per volume increases too. As the air cools down in the receivers and lines, it's capacity to hold water decreases and condenses throughout the system.

There are a few ways to combat this problem. Some systems simply have valves that release air at the bottom of the tank which removes the water. They can be manual requiring a maintenance person to open the valve or an electromechanical valve that opens automatically. Another way to do this is to use a refrigerant drier. This is basically a dehumidifer build right after the compressor to condense the water and drain it before sending it to the system. Power Tower, Skyhawk, and the newer Intamins use refrigerant driers on their pneumatic systems with automatic valves to discharge the water in the unit themselves. There are other driers that get the air pretty close to 100% dry that use desiccants. This would be overkill in this case.

Any roller coaster historians out there? John Miller, called "the Thomas Edison of rollercoasters" because he had so many patents, was the inventor of the original "clackety-clack" device. He built from the 1920's-1950's, when wooden coasters ruled. The Big Dipper at GL and JackRabbit and the Racer twin/dueling coasters at Kennywood are original Miller coasters. I think I read where he felt the noise heightened the anticipation of the first drop...but regardless, it's part of a classic coaster experience to hear the racheting. Thanks for letting me enjoy Cedar Point from afar (I live in his hometown of Homewood, IL) through these forums!