Monday, April 18, 2005 11:38 AM
I was wondering the internet, and I was just wondering. . . what are the different types of blocks that roller coasters hae? For example, how does a "rolling" block work, and what is a pseudo(sp) block? Thanks a lot!!
The number one reason you know you are an engineer: The world revolves around you because YOU chose the coordinate system.
Monday, April 18, 2005 12:00 PM
This screams for a RideMan essay :)
Monday, April 18, 2005 12:09 PM
Since Dave's a busy guy, and nobody likes repeating themselves...(well, cept me, but I vary the story a little each time to flesh it out, LOL)...
Monday, April 18, 2005 4:17 PM
The only ride I know of that uses a rolling block is MF. The load and unload areas consist of 3 blocks. When the end becomes clear, the block behind is extened 1/3 into the next block. As the middle block clears it turns into 2/3rds of the block. As the 1st train exits the block, the 2nd train is allowed to approch the end of the block.
It's not perfect, but it works.
No ride uses pseudo or pseudo rolling blocks.
Monday, April 18, 2005 4:24 PM
That's pretty cool about MF's blocks, I had never heard of that before. Does TTD work in the same way? I had read somewhere that there are some 10 sensors per block on TTD so they could roll 2 trains along at the same time... Am I way off here, or pretty close?
But then again, what do I know?
Monday, April 18, 2005 4:32 PM
ShaneDenmark, there are close to 2000 proxy sensors on TTD to allow it to move trains like it does.
If you can't stand the heights, get out of the line.
Monday, April 18, 2005 5:18 PM
I doubt that. There are a great many prox switches, but most of the "sensors" on the ride are plain vanilla switches. There are at least two for every retractable brake fin.
Monday, April 18, 2005 6:28 PM
I think the real number of proxies on TTD was somewhere around 600, although I really don't remember. They have tons of proxies throughout both the load and the unload stations and the holding blocks. I think they went overboard in these areas since they have never moved the trains close together or "in pairs" like they do at MF. They also have them on some of the gates leading to under the ride and assuming they have the same system as other rides at CP, on the airgates as well.
Monday, April 18, 2005 11:27 PM
TTD uses over 600 proximity sensors. They are used in 4 different positions to detect trains.
Most of them in the station are located in the block reset position. If you look at the ride closely at night, you can see amber LEDs light up when they are switched on. The only place on the train that activates them is a plate on the inside of the last right wheel assembly.
There is another row near the top middle of the track which is switched on for the length of each car. There are 2 other positions only used in the launch position.
There are some used on the transfer table, airgates, lapbar release contacts, low zone gates, and probably a couple other places.
There are many more limit switches used.
Decending brakes, decending drive tires, transfer, and hydraulics are where these are used, mostly for the brakes though.
TTD could be operated like MF's blocks without running at a higher speed. In that case, there would only be a need for 2 block resets per block. That would be 18 as opposed to the current number of around 120.
I don't know exact details, but TTD was intended to run the trains faster than they do now. The inverters usually run at 35Hz which is about a fast walk. Inverters usually are capable of 120 Hz. I can pretty much rule out they were going to use 120 Hz as that is over 15 MPH. The problem is that the trains don't run as they calculated. The curve in the unload station is simply too tight. The drive tires cannot reliably stop trains in position as they had planned for. The reason is the tires do not make static contact with the train 90% of the time. They also have a short life. This is why it hasn't run as intended since 2003. As of right now, TTD uses regular blocking and wastes many sensors.
Tuesday, April 19, 2005 9:23 AM
Sounds true to me about wasting most of those sensors. The big question I would have is whether the code is still needlessly keeping track of all these extra sensors. It would seem to me that if they aren't performing any real function, they should be removed from the code and probably physically removed from the ride. Why have more pieces of hardware to potentially cause problems if they are not doing anything? They could remove the extras and have spares for the next 15 years! ;)
Wednesday, April 20, 2005 2:15 AM
I don't know if the program still has errors for the sensors that are not used. I don't even know if they still have the "dry" mode in the program still. If they do salvage those parts, they will have several input cars for the PLC that could be used as replacements if other burn out. The 100+ sensors could be used to replace the same type of sensor on any ride in the park. The sensors are designed to last a very long time. They probably have some extras as there are always bad parts in mass production. They might last a while, but they will fail prematurely. For now, it's probably easier to pull one out of a box than unscrew one from the ride.