Someone please tell me Xcelerator is safe

Friday, July 5, 2002 8:50 PM

Sorry if I sound like a one-track record. After the launch, the brake fins pop up. What is the fail-safe for that? See, they would be connected to the PLC via cables or hoses. That is not 100% safe, think S:ROS.

The above is quite different to the brakes on Giant Drops, standard anti-rollbacks & anything else that applies. These are simple & do not rely on any external power.

Friday, July 5, 2002 8:57 PM

Easy, the power off configuration is fins up, and it takes energy to hold them down. So in case of a pneumatic or electrical or whatever failure, they just pop up. No problem.

ASTM spec for roller coaster design requires that brakes fail into an engaged mode.

12.2 Design critical braking systems to be energized systems which remain activated in the event of power failure where appropriate.

-ASTM F1159-02

Friday, July 5, 2002 9:16 PM
I remember one Arrow suspended coaster had the fail position of the brakes open... God what was it, XLR8? Can't recall...

.:| Brandon Rodriguez |:.

Friday, July 5, 2002 9:29 PM

That would actually make XLR8 a thrilling ride if the brakes failed.

A loss of power isn't a concern with most coaster brakes, as they indeed engage when there's a short. The real problem is bugs that might occur in the computer controlled automation. A software glitch could cause the brakes to not engage for some reason, unlikely but possible.

Saturday, July 6, 2002 5:12 AM
Let's just put it this way, you wouldn't ride it if it wasn't fine.

Can we change the name of Top Gun to your mom so no one wants to ride your mom?

Saturday, July 6, 2002 5:46 AM
The only brake failure I can think of that puts the brakes open is on RCT.
Saturday, July 6, 2002 7:32 AM
Actually, Arrow and Vekoma both use braking systems where air pressure is required to inflate the bladder and therefore to close the brake. Besides the fact that the system was designed before ASTM F 1159-02-12.2 was written, they take a slightly different approach. The brake caliper is fed air via a (held closed with power) solenoid valve from a reserve pressure tank equipped with a check-valve. And adjacent calipers are fed from different pressure tanks. And there are more calipers than needed to stop the train. If power is lost, the valve opens and air flows from the pressure tank into the brake. If the compressor fails, there is enough pressure in the tank to close the brake. If the line from the tank to the caliper fails, the next caliper will stop the train.
And let me point out that mission-critical pressure-applied braking systems are actually quite common. If you have a car, that what it uses.

--Dave Althoff, Jr.
Sunday, July 7, 2002 12:27 PM
Xcelerator is safe.
(Was that really so hard?)

Joey Ciborek, Florida Coaster Club, Member
"It's like an addiction" Me, The Discovery Channel, Ultimate Guide: Roller Coasters 5/27/02

Sunday, July 7, 2002 12:31 PM
Coasters are safe, and that includes Xcelerator.
Sunday, July 7, 2002 12:51 PM

Leave it to Rideman to make the point in the most easy to understand, albiet technical, verbiage of all! Dave, I salute you.:)

How are you doing, Kevin? Xcelerator got you nervous? I will let you know in a few weeks exactly how frightened I was.;)
Dream on!


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