Cedar Point guest hit by Top Thrill Dragster part while in queue

If I recall correctly, Gemini uses old-school AB photo eyes on the track instead of proximity sensors. In theory if water gets on the lens it could obstruct the signal and cause false sensing, but those same photo eyes have been used on Arrow log flumes for years with minimal problems of that sort. Usually they just put a splash guard over them.

Just out of curiosity, we've talked a bit about Kingda Ka, and it seems to be running. What about Xcelerator at Knotts? I would assume it is somewhat similar to TTD in some manners.

OhioStater said:

In this video you can see both trains moving out of the station...

What PhantomTails said. They're not overlapping blocks here, as the forward load block is clear before the second train moves. That's the reason they have sensor mania, to facilitate bumper to bumper movement, and they don't actually do it.

Walt S said:

Just out of curiosity, we've talked a bit about Kingda Ka, and it seems to be running. What about Xcelerator at Knotts? I would assume it is somewhat similar to TTD in some manners.

I’m guessing they checked those bolts or replaced them with known high quality Grade 8 hardware on the other accelerators.

As I'm sure almost everyone knows, Dragster was originally designed to operate with all six trains. When they actually got the ride going, they found that it was more efficient to run with 5 trains. I don't know if how much that had to do with getting the simultaneous bumper-to-bumper working. However, once the decision was made to only run 5 trains, why didn't they remove a bunch of the sensors? It seems to me that there are 5 to 10 times the number of sensors needed to safely run the ride. I suppose they could have written the PLC logic to ignore single sensor failures, but I doubt that would happen.

I figured that it didn’t make sense to run 6 trains when they had to abandon having all the trains move up at the same time. When the train on load one moves up to launch it would have to wait for all the other trains to move forward two positions before the final block would clear such that it could launch.

0g said:
As I'm sure almost everyone knows, Dragster was originally designed to operate with all six trains. When they actually got the ride going, they found that it was more efficient to run with 5 trains. I don't know if how much that had to do with getting the simultaneous bumper-to-bumper working. However, once the decision was made to only run 5 trains, why didn't they remove a bunch of the sensors? It seems to me that there are 5 to 10 times the number of sensors needed to safely run the ride. I suppose they could have written the PLC logic to ignore single sensor failures, but I doubt that would happen.

I have to wonder if part of that might involve certification and design of the control system. If this were avionics or the automotive industry, such a change would mean quite a lot of testing and recertification of the systems. I could possibly see a lot of PLC reprogramming being necessary to remove sensors.

Perhaps more simply, using a control system designed for six trains to operate with five suggests that the limitations on the system mean that a control system designed for six trains was readily adapted to work with five...but if they cut the system down so that it was optimized for five trains, they might have trouble running more than four.

It's kind of interesting...Intamin's tactic with the dual stations (Avalanche Run, Dragster, Maverick, just to name the Cedar Point examples) is that for loading and unloading purposes they treat two trains as if it were a single train, then split them apart to operate on the ride with much shorter headway than they could achieve with fewer trains. The idea is that the process that takes the longest, and over which the Designer/Engineer has the least control, is loading and unloading. So put two trains in the station and you can have your 75 seconds for loading and unloading, and still dispatch trains into the ride on a 38-second interval.

But running an odd number of trains makes that a kind of a strange process as the "train" that loaded as 1+2 ends up unloading as 5+1.

--Dave Althoff, Jr.

RideMan said:

Perhaps more simply, using a control system designed for six trains to operate with five suggests that the limitations on the system mean that a control system designed for six trains was readily adapted to work with five...but if they cut the system down so that it was optimized for five trains, they might have trouble running more than four.

It's kind of interesting...Intamin's tactic with the dual stations (Avalanche Run, Dragster, Maverick, just to name the Cedar Point examples) is that for loading and unloading purposes they treat two trains as if it were a single train, then split them apart to operate on the ride with much shorter headway than they could achieve with fewer trains. The idea is that the process that takes the longest, and over which the Designer/Engineer has the least control, is loading and unloading. So put two trains in the station and you can have your 75 seconds for loading and unloading, and still dispatch trains into the ride on a 38-second interval.

But running an odd number of trains makes that a kind of a strange process as the "train" that loaded as 1+2 ends up unloading as 5+1.

--Dave Althoff, Jr.

Indiana Jones is an Intamin coaster at Disneyland Paris and it works like you said. Both trains in the station leave at the same time, with one going straight to the lift hill and the other wait on the holding brake before the lift hill.

Running 6 12 passenger trains, they get 1600 pph on it. Running 6 is a challenge though, so they tend to run 5 trains normally.

I wonder if the block arrangement at the end of Dragster is why CP decided to run it with 5.

Seen on a Facebook group...