B&M invert safety question?

So what happens on a b&m invert if a train "valleys" or gets stuck? I don't know that much about ride mechanics but it seems to be most rides have a evac point or mcbr that could be used to stop a second train if the first stops accidentally.. But, on a invert it seems the only place the train could be stopped is on the lift hill. Is the first train complely clear before the second is released from the lift hill? Or what?

I've never actually operated a coaster but from my observations and what I've read on here:

All roller coasters are split up into multiple logical blocks. A ride must have at least (# of trains) + 1 blocks (4 blocks for 3 train operation, 3 blocks for 2 train, etc). The ride control systems always ensure that the block ahead is completely clear before allowing a train pass through...unless you're riding magnum in the rain but that's a whole other can of worms.

For example on Magnum, a train will stop at the top of the lift if the other train has not cleared the safety brakes at the end of the last tunnel. Raptor will stop at the top of the lift if the other train hasn't passed the MCBR. Millennium Force will stop at the top of the lift if the last train hasn't moved completely into the unload station. Basically if the block isn't clear, the train is getting held. If the computer flips out and loses track of what blocks are occupied it will initiate an e-stop and stop everything.

I know RideMan would be able to describe everything in great detail.

Since you asked about raptor it works like this. You have the station, the lift, the mid-course brake run, and the brake run leading into the station. The train will not proceed into the next part of the track unless the previous train has cleared.

The train leaves the station only after the lift is clear, the train leaves the lift when the MCBR is clear, the train leaves the MCBR when the block leading to the station is clear. The train enters the station when the station is clear. Repeat.

However the block system has failed on raptor before... and it put 2 trains on the lift.

I think I accidentally deleted my reply while editing, ugh. So I understand that part now but it raises another question if the mcbrs could exist without somehow being seen or felt by riders? I obviously notice them on other rides but perhaps they are just more exposed on those rides. I am familiar with raptor but my home parks invert seems to only have areas that could be sensing trains on the lift hill and right before the station. Is it possible that there is nothing between these areas, on the actual track, that traces the rides location?

You only need to know when a train enters and exits a block. You don't need to know it's location every foot along the track.

Watch the timing of the trains from a distance. If there's no MCBR I bet the brake run at the end is clear before the train tops the lift. Note too that some rides (Dragster, Maverick, and I think Raptor come to mind) will have 2 blocks in 1 brake run. Most rides are engineered so you don't have a lot of downtime waiting on trains to clear blocks. Usually the interval is short enough you're (ready) trying to get trains out of (ready ready) the station before they (clear!) stack.

I'm pretty sure you can put proximity sensors (those little green boxes all over the place) pretty much anywhere on the track to help keep tabs on where trains are, how fast they are moving, etc. I believe there is one on the other side of Dragster's crest slightly past the point where you're too far over to rollback that allows the staging train to advance to the launch position. It will not launch however, until the safeties are clear.

RideMan and anyone else who knows more about these rides please correct me if I'm wrong.

You are right and every rides a little bit different but yeah, that's basically how blocking works. In fact there were multiple blocks on Disaster Transports lift. The second shuttle would dispatch when the first was 2/3 or so up the hill.

It's basically an anti collision system. The goal is to insure that whenever you let gravity (or propulsion take over if a launched coaster) That the train that came before it is in no danger of getting rear-ended by the second one.

Lets say that going through the loop, Raptor loses a wheel assembly, and the train comes to a stop before the cobra roll. At this point the lift was an open block so it's possible the train could have been dispatched. Lets say that it has and the third train is entering the station.

The second train would stop on the lift, even without a manual e-stop, which if it valleys is quite possible and likely. But lets just say that only the computer notices. The ride computer would see that the broken train has not cleared the mid course brake run, and would know that that block is occoupied. Now, the point of blocks become apparent. The ride computer would halt the train on the lift, because it has one job. Do not put 2 trains on the same block. At this point... lets say the ride ops are completely out of it, and try to dispatch the train. It would not let them, as the lift is now an occupied block.

The whole point of the entire system is NEVER allow a train into an occoupied block.

Lets say it brakes down in the helix. In this case, the second train would stop in the MCBR, and the 3rd would stop on the lift. That it if the ride ops didn't notice before they dispatched the train (and they probably would)

I'll let Rideman explain:

http://www.davealthoff.com/tech/blocking.html

Edit: Fixed that link for you. --DCAjr (Yeah, I can do that. I generally don't.)

Maniaman said:

...I know RideMan would be able to describe everything in great detail.

I don't think I need to bother; you've covered it pretty well. Even so, liebevision gave a pretty good explanation of what happens when things go wrong, but gave you a link to a page that will disappear without warning when someone figures out how to decommission the server. If you want to read that article, go here instead:

http://www.davealthoff.com/tech/blocking.html

913girl asked...
I think I accidentally deleted my reply while editing, ugh. So I understand that part now but it raises another question if the mcbrs could exist without somehow being seen or felt by riders? I obviously notice them on other rides but perhaps they are just more exposed on those rides. I am familiar with raptor but my home parks invert seems to only have areas that could be sensing trains on the lift hill and right before the station. Is it possible that there is nothing between these areas, on the actual track, that traces the rides location?

Yes, you did. But you got your question out anyway. :)

The mid-course need not actually affect the progress of the train if the block ahead is clear, which is why you can sail through the brakes on Raptor without feeling or hearing anything. But you revealed that you're not talking about Raptor. Hmmm...I'm going to guess that you're talking about Patriot, which is a little different from Raptor in that it only runs two trains. Because it only has two trains, it only needs to have three blocks. That is covered by the station, the lift, and a safety brake between the lift and the station, and immediately uptrack of the station. That would be just *past* the magnetic brakes (which Raptor, being an older ride, does not have) where the train can stop just before entering the station. If you watch, you will see that it takes less time to move the train from that brake into the station than it takes to get from the station to the top of the lift, so most of the time there won't be any delays or anything else. Once a train is dispatched from the station, there is plenty of time to get the other train parked in the station before the first train clears the top of the lift. Two-train coasters are pretty easy.

That said, we've covered blocking pretty well, but what about evacuation? The ride is constructed in accordance with the ASTM design standard in effect at the time of construction; for Raptor that would be an early version, I think, of F 1159. But even the earliest standards required maintenance of a passenger clearance envelope around the train. This means that it would be impossible to include an evacuation platform anywhere on the ride that could allow riders to evacuate. So how do you get people off if something goes wrong?

It turns out that B&M keep it simple. Beneath the block brakes, there is a full platform with handrails and everything. If you look around on that platform you should see a little metal "step" on wheels about a foot high, a little wider than the train, and a little deeper than the space between cars. That platform can be rolled in under the train, an attendant can manually release the shoulder bars for one row of seats, and those people can step off. Then the platform is rolled to the next row, and the process repeats. The lift hill is a little more complicated. There is a little vehicle with a gasoline engine (operating under the theory that the need to evacuate from the lift hill might be caused by a power failure) that rides on its own track up the lift hill. It can be driven in underneath the train, which is then evacuated in the same way as on the mid course brake. The platform on this little vehicle allows riders to access the stairs beneath the lift hill.

Of course, if the train valleys in the cobra roll, things get really complicated, but the process is the same as for any coaster: secure the train to keep it from moving, bring out a scissor lift or bucket truck, extend the lift to the train, unload one row at a time.

--Dave Althoff, Jr.
(Curious: Am I right about the "home" coaster being Patriot? :) )

Are you ever gonna start using twitter again, Rideman?

Again?

I opened a Twitter account because I wanted to get a message to someone who didn't offer any other method of contact. I subsequently set up an ifttt recipe to put a notice on Twitter if I post a new video to blip.tv. Other than that I've pretty much never tweeted. See for yourself: http://twitter.com/RideManDave (RideMan was taken by someone who also never tweets...)

--Dave Althoff, Jr.

Alright, great. All my questions are answered. At least for this topic(; you're right about patriot. Best invert if you ask me! The fact that there is 3 trains is what confused me because I figured that the blocking would only fit two based on the areas you mentioned, those were the only ones I could identify! I had to wonder if the other was a backup or just for a really busy day I hadn't witnessed myself but I suppose a backup it is. Thanks guys!

I just saw that your last tweet was back in October and I was just curious.