Mean Streak brakes?

i got this email from the director of maintenance and construction a while back

Ed Dangler:
The trim brakes on the Mean Streak are controlled by the computer control system. We measure the speed of each train. Depending on the measured velocity the computer control system may allow the brakes to stay on in a trim brake mode. The brakes then may be closed in a trimming function for longer or shorter periods of time as a result of the measured speed. We do not have plan to remove this brake control system.

Nice to see that my speculation earlier in this thread is, in fact, rooted in some truth...

Here is some more detail. The brakes used on Mean Streak use a spring loaded air cylinder to operate. In practical terms, this means that unlike the air bladder brakes used on the Arrow coasters (other than Mine Rilde) which can be adjusted by varying the air pressure, the Mean Streak brakes can really only be "closed" or "open". When they are closed, the braking force is provided by the spring.

What this means is that the amount of braking action you get on the trim brakes is controlled by the amount of time that the caliper remains closed. Because unlike the spring tension, the brake timing is adjustable. The brake can engage later, so that the train is moving faster when the brake engages, or it can be engaged for a shorter period of time.

The problem is that because the brakes are mounted high on the first drop, there really is no way to get a meaningful measurement of the train speed before it reaches the brakes, so there is really no good way to adjust the braking action for the actual train speed. Instead, the train speed has to be measured after it exits the brake. A statistical analysis can then be performed on that train, and the brake timing can be adjusted for each subsequent train.

Of course, this means there is some latency in the brake adjustments, but most of the time the train is consistent enough that it should not be a problem.

I wonder if the park has ever considered moving the trm brakes to the second hill, just below the curve. That would easily accomplish three things: first, it would allow the train to achieve its proper top speed again. Second, it would allow for an accurate speed measurement before the train reaches the brake, allowing the braking to be adjusted for the train's actual performance instead of its statistical performance. And third, it would move the braking action to a location where riders expect the train to slow a bit anyway (going uphill). It would certainly reduce the "Toothchipper" effect. The one problem I would expect is that because gravity isn't trying to force the train through the brakes, it would make the brake more likely to stall out the train.

I also wonder why they have not opted to use a bladder type brake for the drop trims, because while an air applied brake is not inherently fail safe, it is much better suited to use as a trim brake, simply because adjusting the air pressure will effectively adjust the braking force.

--Dave Althoff, Jr.

I'm glad I'm not the only person to notice this phenomenon because I was wondering if I had imagined it! I was there on Thursday 7/26 and either Mean Streak's trims didn't fire on the first drop or else they were just much less noticeable than in any other ride I've ever had in the years I've been riding it (since 2001 or so). I guess I got lucky! I was really surprised.

I rode on 7/30 and 7/31. All 3 rides used the trim brakes.

Glad to see that it is a much better ride after years of avoiding the ride.

I was on yesterday, my only ride had the trims on HARD. It was around 11AM. The whole ride was jackhammering, so awful.