Dragster Question

ahh, thanks for that I understand now, I was concentrating to hard, I thought it was someting irregular and did not see it all over the top the coaster. Thanks, I guess something clicked and figured out what you said.

Good to hear. We'll ignore the fact that it took you 5 months to get it. ;-)

I always thought it was for placing the sensor up on the tower. The sensor wouldn't get in the way of the train. It is most likly for clearance over the top though.

The sensors are placed in between the ties; there is no reason for them to be placed differently on the top of the tower. Take a look at where they're located here. The sensor theory would mean that the number of sensors would be limited to one per horizontal tie, which just doesn't cut it on TTD--just look at the number of sensors in the station alone! :)

*** Edited 2/20/2005 1:52:18 AM UTC by PhantomTails***

haha, yeah it is pretty patheic. oh well

http://www.pointbuzz.com/Gallery.aspx?i=713

There are two rows of sensors. The line of sensors on the right side near the rails and a few towards the center placed at seemingly random interval.

The best video I've seen to visualize this is at pointbuzz. Check out the "waiting" video.
http://www.pointbuzz.com/topthrilldragster-v.htm

If you observe very closly, you can see that the sesnors in the middle are responsible for slowing then stoping the train into position. There is an angle bar on the train that sets these proximity sensors. They run basically the length of the train. The angle bar starts just before the first wheel assembly. You can get a halfway decent reference from there to the sensors that are responsible for slowing and stoping the train.

The line of sensors on the right side of the track are all for block resetting. The only place on the trains the set this sensor off is the last wheelset of the train. The only time you can see this is at night by the launch position. The sensors that are triggered have a amber (orange) light. These sensors are actually arranged in pairs. The only time that all of the sensors are needed, is when there are 6 train operation in dry mode (fast mode).

For regular operation mode known as "wet mode." The sensors reset the entire block such as when a train leaves load 1, a particular pair resets the load 1 block so the train in load 2 can proceed. This is regular blocking in most roller coaster.

I'll explain MF first because it's an easier concept. There are three mirco blocks on MF in the unload station. There is one front, the middle and the end. A train parked in the station occupies all three. When the ride is dispatched (assuming 3 trains) the train in unload will proceed to load. As soon as the end is uncovered, the train in waiting proceeds. The timing between the two trains is exact. Either the front, middle or the end with be uncovered untill the train going to load clears the unload station. This is done with a different set of block reset sensors located just past the unload station. Simular to TTD but on it's side close to the right of the track.

TTD has many microblocks to allow the trains to run closer in dry mode. The idea is to have the hold 2 clear before the first train reaches the launch position. In theory it works, in the real world if fails miserably. The problem is partially that the train in unload can't accelerate nor decelerate fast enough. Can't run in outside the stopping position slowly or the train stalls, and the trains bump into each other easily in the process. Another reason why this doesn't work is the reaction delay. A small ride has few inputs to read, outputs to write to and a small program. TTD has a very large program, many inputs and outputs. It takes upto 2 complete program cycles to make a change. The reaction time with this type of train movements needs to be very fast, but it gets bogged down by the overall program. It's been tried many many times to try to get 6 trains to run in dry mode. They have simply given up on it.

As for the grooves in the track. The beam in the center of the train is the contact point for the drive tires. Since this bar is straight hanging between the cars wheelsets, in it's center it lifts up in reference to the track on steep curves concaved up. MF's pullup onto the lift for example. On TTD the tophat is concaved down. This means the center is going to get very close to the track, and at the tophat would be an interfernce point. That is why the groove was set there. Also, note the width of the groove.

Millennium Force has a smaller groove for the chain dog in some locations as well.