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http://www.islandguide.8m.com
all about PKI
SOB/TG crew in 2002
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- Peabody
What happens is they can rise up...and drop down so if a train stops they rise up and stop it...and if it is ready to drop is drops down and the train can roll backwards.
That thump you feel on the second lift is the anti-rollbacks and chainlift coming up to catch the train...atleast that's what I always thought it was.
Can anyone verify this?
You can hear the pnuematics cycling.
jeremy
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"Nobody writes about the planes that land." Steve Salerno Washington Times 7-10-01
On F/O at PKI, there is something that does release when you are at the top of each drop. I dont know if this is part of the grabbing mechanism, but it releases and you go downward. The reason the brakes are at the bottom is for a miscatch, so you dont keep going in between the loop and anywhere else (in case you do have enough speed to go over the loop again). Thats a much easier spot to get people down from.
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http://www.islandguide.8m.com
all about PKI
SOB/TG crew in 2002
There are no anti-rollback mechanisms on the Boomerang or Invertigo coasters, but the lift mechanisms of the two coasters are very different. Both use the same "Bad Thing Protection" mechanism.
On the Boomerang, Lift #1 uses a claw mechanism mounted on a catch-car and pulled by a wire rope to haul the train backwards up the lift. As the train leaves the station, the station brakes close...the idea is that if the hoisting cable breaks, the catch-car lets go, or other Bad Things happen, the brakes will slow the train enough that it won't complete the first inversion and will roll back into the station. When the train reaches the top of the lift, the station brakes open. Finally, the catch-car passes a ramp mechanism that opens the claw, releasing the train. The train heads down the drop, through the station, through the three inversions, and up Lift #2. As the train passes the brakes at the base of Lift #2, those brakes close. Again, the brakes are intended to slow the train if there is an early release so that it will valley between the vertical loop and the lift instead of between the two sidewinders 80' in the air. Lift #2 uses a set of conventional chain dogs on the train, and an almost conventional chain lift. As SFNE Freak pointed out, the chain lift is mounted on a pneumatic cylinder so that once the train reaches the top of that lift (and the brakes at the base of Lift #2 open), the entire lift assembly...chain, chain guide, bullwheel, idler wheel, motor, etc....drops back perpendicular to the lift track, releasing the train so that it can roll backward down the hill.
The THUMP! and lurch that B&M-TYCOON is talking about on the second lift happens because when the train reaches the chain lift, the chain lift is either stopped, or has just barely started moving. So the train tends to overrun the lift, then drop backward until the chain dogs engage. You can hear the dogs jump over the first few links of the chain before that happens. Both lifts on the Boomerang use hydraulic motors, so they are stopped when not actually lifting trains.
On the Invertigo, things are somewhat different. The brake timing is the same as on the Boomerang, but the lift mechanism is different...but basically the same on both lifts. A catch-car waits at the base of the lift for the train to arrive, moving up the lift at a speed to match the train. As the train engages, the catch-car closes what is essentially a brake caliper on a fin on top of the train and pulls the train to the top; at the top an external trigger opens the caliper to release the train. By matching the speed of the catchwagon to the speed of the train, the engagement is much smoother than on the Boomerang, where the traditional tooth-shattering chain clutch is used.
Any questions? :)
--Dave Althoff, Jr.
2Hostyl said:
No anti-rollback per se, but they do all have a brake between the vertical loop and lift two. This brake closes when the train is engaged on either of the lifts; opens when the train is successfully raised to the top of either lift; and closes right after the train passes it.
You can hear the pnuematics cycling.
jeremy
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Wow. You know, now that you bring that up, I remember seeing that when I was in line for Face/Off. I remember learning when it would open and close, too, since I was in line for so long. Neato.
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My wishlist for the 2002 season includes 121 different coasters, 92 of which I have not ridden.
How are the catch wagon and the train synchronized on an Invertigo so that they are going at the same speed?
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SFNE loses its "floor" for 2002! Visit www.geocities.com/sfneguy for info. and pics of SFNE, including the most unique constr. pics of SFNE on the web. Formerly known as srosatsfne.
I am not sure but I wonder if a sensor on the track could measure how fast the wheel assembly's are going by. I think it could be done...basically the same principal.
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