Tuned mass dampers(?) added to TT2

What appear to be tuned mass dampers have been added to one column each on the pull-up and pull-out of TT2, just south of the original tower. See the YouTube link below for video of the device in action.

Damper on pull-up column

That's super interesting. They use things like this in buildings to counteract the effects of earthquakes and wind (great story on Veritasium here). It's a clever solution, though I'd like to compare to video from before. Also, I wonder why they didn't do new triangular supports like those that were on Kingda Ka. I thought much of the "wiggle energy" came from stopping of the catch car in the old configuration, but I know it was still serious.

Yeah, definitely interesting. In the video, there is still a good deal of sway, but don't know how much there used to be. And, I wonder if the dampers as opposed to adding triangular supports was a temporary measure, a cost-cutting move as opposed to adding diagonal bracing, or if there was an engineering need to allow the track to still sway a little bit as opposed to being made more rigid.

I feel like maybe adding rigidity to the track (i.e. additional cross bracing, triangular supports) might have transferred the additional force onto the trains, whereas this damper solution helps the structure absorb it but then dissipate the swaying. But like, the math on my napkin is sketchy at best.

Would this (or the severity of it) be worsened by the multi-pass launch? I.e. any movement caused by a passing train would be able to dissipate prior to another launch with the old configuration ... but now, the train that made it shake will be back almost imminently ?

Forward only, it ran for two decades. The old trains seem heavier, but not nearly as high over the track. And as I mentioned, it also had to deal with the stopping of the catch car, going 120 mph to zero in a short stretch. I guess what I'm getting at is that the ride dynamics are very different.

I haven't yet seen detailed photos of the trains, so there is more to armchair engineer!

Yeah I follow, I guess I meant more that if the structure was jiggling after pass one, it would perhaps jiggle more as the train returned on the first rollback and still not be static by the time the train returned to go over the hill.

Sounds like it performed quite well over the weekend. I read somewhere that MF valleyed, is that quite rare?

I was at the park today after taking a half day at work to try and get on Dragster 2.0. To my suprise, it was up and it didn't break down the hour I was in line, nor did I see it down at any period while at the park.

The ride ran great, IMO. I didn't ride it last year during its week long showing, but it felt like typical Dragster to me in terms of feeling. Maybe even a touch smoother honestly at top speed going up and down the tophat.

That being said, Dragster lost the "it" factor for me. That launch is just no comparison to prior, which was the best part of the ride IMO. I think a Prius has more punch off the line... haha

The back spike is cool and tons of float with great views, so that is a nice at least. The trains are also a huge improvement in comfort, much better than the old trains.

Also, the mass tuned dampers work well. Great use of them... They are also used on Lost Gravity in Holland for a similar oscillation issue.

I have no idea what I'm watching happen in that video.

Track wiggle to the right, mass go left. Track wiggle to the left, mass go right. Cancel out movement/oscillation.

The dampers appear to be about halfway up the curve, near the top of the support. That was about where it would sway the most.

As far as why they choose the damper over additional bracing, I suspect there could be two reasons. First is probably cost. Adding a damper is probably a lot less expensive than putting in a new support and footers. The second may have to do with how rigid the structure is. If a structure is too rigid, it is weaker than a structure that can sway. With the damper, the track can still sway, but it won't just keep oscillating like the old ride did.

That makes me wonder, why they decided that TT2 needed the damper, but Top Thrill Dragster did not.

Honestly, could be as simple as the desire to smoothen the approach up into and out of the tower (while on ride). Even though it happens quickly, when that train is going through that section of track at a high rate of speed there is likely oscillation occurring causing some on-ride 'shimmy' that they were trying to eliminate. Sure, it could have been just fine without, but with all the troubleshooting of train issues, repairing/alignment of the track and overhauling the trains, why not add a mass damper in two places to improve it even further? It probably was fairly low cost relatively speaking. Doubt it was due to 'structural issues' as it behaved that way since 2003 just fine. My bet is on comfort.

It *could* also be the change in excitation forces applied by the new train, but I don't buy the swing launch really making things 'worse', as there is such a long period of time for the track to settle down and the first 'swing' up the tower isn't exactly all that stressful on the structure.

Just my .02 though.

I’m not sure exactly what they did, but somehow TT2 is smoother this year than last year. Rode it once on Saturday and then rode it 7 times on Monday, and it’s so smooth now compared to last year. I really like front row on this, you just get great views

The question is, does it ride with any lateral shimmy at speed? It was super noticeable last year, though not to the point of discomfort.

Not a physicist, so just theorizing, but perhaps the switch from a cable launch to LSMs had something to do with it? With a cable launch, the torque is transferred to a concrete pad that is independent of the ride structure. On the other hand, the LSMs are bolted directly to the ride structure, so the force of propelling the train forward/backward is transferred directly to the track and supports.

I didn't really notice any shimmy outside of what Dragster always felt like at full speed. You bounce around a little, but I wouldn't call it abnormal or out of the ordinary. I didn't ride it last year so I can't compare to "pre-fix", but it felt... normal?

Jeff:

The question is, does it ride with any lateral shimmy at speed? It was super noticeable last year, though not to the point of discomfort.

From my 7 (!) laps on TT2 on monday, I did not notice nearly any lateral shimmy. There is a little, but that is to be expected at 120 mph on 20+year old track, but it rode so comfortably, and it blew me away how fun it is.

How much of the track is original at this point?

I'm pretty sure all of it is original except for the rear spike and the station and turn-around.

Presumably the launch track is also new.