SFNE Freak said:
What happens if they E-Stop it there? Where's the momentum to get it to engage on the lift?
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SFNE Central- Online Six Flags New England Resource
Devoted Intamin Lover for Life!
I dont know if this is right, correct me if I'm wrong, but aren't there wheels on some brakes just in case that happens? While waiting at the gate one morning at Cedar Point, I was watching Raptor's test runs. When they stopped the train completely over the MCBR, they let it sit there for a minute then the brakes opened and the train was pushed out of the brakes and continued down the drop and through the rest of the circuit. The train was completely level, so the front of it could not have been part way down the hill and pulling the rest of the train, so if there are no booster wheels in some brakes could someone please explain to me how Raptor does this?
Isn't it just very gently graded downward? And no, NI doesn't have advancing wheels at that point if you look in photos.
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"Launching in 1,2,3..2..1"
-Wicked Twister Ride Op.
Ultimate Coaster said:
Phantom, I see your point, but does gravity really pull trains that fast? Raptor's brakes would open and the train would start off faster (or so it seems) then gravity would let it. The train would go about the speed of the lift hill coming right out of the brakes without time to speed up.
The trains do weigh a lot and I'm sure it doesn't take a lot for them get rolling at a pretty good speed.
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SFNE Central- Online Six Flags New England Resource
Devoted Intamin Lover for Life!
SFNE Freak said:
I don't think B&M's have brakes before lifts, just advancing wheels.
For the most part, I think you are right, but I think Nitro has a brake before its lift.
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-Matt
2001 Magnum Crew
*** This post was edited by MDOmnis on 12/29/2002. ***
PhantomTails said:
Gravity! If there are no booster wheels, then the designers just put the MCBR at a slight angle so that gravity makes the train roll forward when the brakes release.
As shown here on The Riddler' Revenge http://americacoasters.com/Photos/SFMM/rrv1.jpg
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SFNE Central- Online Six Flags New England Resource
Devoted Intamin Lover for Life!
Riddler and Mantis both have advancing wheels and brakes before the lift...this might be due to the fact that they used the vertical wheels instead of the pinch drives they use more often now. Slippage is more likely on the vertical tires than the pinch drives.
An example of the slippage is on Goliath...when the train stops it kinda rocks back and forth. Riddler does this too but isn't as noticible.
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"ok everyone go ahead and pull down on your shoulder restraint so you feel nice and stuck!"
Fair enough - but your definition is inaccurate, as a E-Stop does not close trim brakes does it?
Maybe I should rephrase. Any brake that opens on command from the control system will close on E-Stop. Magnetic trims operate the same (since they obviously don't close at all), as well as a pressure brake that is simply set at a specific pressure regardless of the speed or position of the train.
The trims at the bottom of the lifts of the Arrow coasters mentioned by the original poster trim based on the spped of the train and are directly controlled by the PLC(s). They will therefore close on an E-Stop. And on at least one of those rides, it is required to PUSH the train onto the lift once the situation is remedied.
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Face/Off Crew '99-'00, Top Gun Sup '00, King Cobra/Days of Thunder Sup '01
Beast Sup '02
Wild Thornberry's River Adventure Sup '02
Ok, I would like to say for the record, that I was recently employed at a major theme park in the US this past summer. I did work in the operations department and in a rides division. Pardon my spelling, I am a horrible typer. I couldn't help but read this post concerning breaks and e-stops.
I'm not sure why there are breaks before chain lifts, but I know for sure, that emergency stops (or e-stops) completely cut the power to the ride. There is nothing left with power, breaks, wheels, lift hill, and anything else on the ride (not only roller coasters). This is for safety and safety alone. I also know that many coasters that may appear to be horizontal with the ground are actually at a slight diagonal so that gravity can put the train forward. Those block brakes that are in fact horizontal do have wheels to push the train out of the trim brakes etc... Also, form experience, chain dogs and especially guide wheels wear easily, so it would be economical for the coaster, and its manufacturer to to install a device to prevent that wear and tear. Breaks seem to be the most beneficial method.
--Dave Althoff, Jr.
edit: All generalizations are false.
*** This post was edited by RideMan on 1/1/2003. ***
Viper at SFMM has them as well Rideman. They are in the station and help advance the train onto the lift. They dont have individual motors like some of the modern rides. They are all powered by a single motor with a long axle that connects them.
But you are correct...most Arrows use gravity to get a train moving and brakes to stop/slow them. Not all Arrows have brakes before the lift. Canyon Blaster at the Adventuredome. Because of that the train often skips a dog when it engages....this could be solved by adding a brake on the run to the lift.
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"ok everyone go ahead and pull down on your shoulder restraint so you feel nice and stuck!"
MDOmnis said:
SFNE Freak said:
I don't think B&M's have brakes before lifts, just advancing wheels.
For the most part, I think you are right, but I think Nitro has a brake before its lift.-----------------
-Matt
2001 Magnum Crew*** This post was edited by MDOmnis on 12/29/2002. ***
I have spent most of my time in line for that ride looking at the flat section just before the lift, and I'm pretty sure it is just wheels, as I have not seen any sort of clamp-type device that could be a brake. It looks as if there are just 6 wheels that match the train with the lift speed, and to help make sure there are no rollbacks with the little predrop out of the station if the train doesn't have enough speed.
Comet Rider said:
Arrow, at least, has always used rotary brakes (rotating tires) at the lift base to more closely match the train speed with the lift speed.
I'm positive that Oprylands Arrow mine train (Rock N' Roller Coaster) had rotating tires before both lifts and throughout the course. And I think I saw them still intact in some pics from the graveyard in Indiana. Edit: Here's a link...scroll down a bit.
http://capital2.capital.edu/admin-staff/dalthoff/adventures/tr2001/usoifp01.html
So, if an E-stop cuts all power from the ride, then what about the pneumatic brakes that require power to operate. How do those function during an E-stop? Or is there enough air pressure for a stop or perhaps it doesn't completely cut the power supply?
*** This post was edited by coasterfreaky on 1/2/2003. ***
The air compressor feeds a reserve tank through a check-valve (that is, air can enter the tank but can't leak back to the compressor). The reserve tank feeds air to the brake bladders through a solenoid operated spool valve designed so that when energized, the valve allows the brake to vent; when power is dropped the valve sends air from the reserve tank to the brake bladders. Block brakes are divided into multiple sections so that multiple tanks feed the calipers in any block brake section so that if an air system fails there will still be enough braking force to stop the train.
Trim brakes lack the reserve tank plumbing and will simply fail open. But they're not supposed to stop the train anyway.
badboy, it is worth noting that more modern Arrow coasters dispense with the pre-lift brake in favor of a variable speed lift motor.
--Dave Althoff, Jr.
I don't know how long Arrow used those systems, but there sure aren't very many of them left! :)
A big part of the Matterhorn patent, by the way, involves the use of governor wheels. In that case they attached the tire to a flywheel and to an electric motor. I suspect that they discovered that while the system worked pretty well with a single car, it's not as well suited to regulating trains. On the other hand, trains allow for more braking surface area.
In Roller Coasters, Flumes, and Flying Saucers, either Karl or Ed (I forget which and I don't have the book handy) claimed that they didn't use that system on any coasters other than Matterhorn...but even if they didn't use the governor system, it's clear that some of the idea behind that system survived into the early mine trains.
Good call, Comet Rider!
--Dave Althoff, Jr.
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