Acela tilt mechanism fails, slowdown creates ripple effect on NEC Options

[PHL]

Just heard from a friend riding Amtrak from NYP to BOS today that an Acela leaving PVD southbound had a tilt mechanism fail, creating a ripple effect througout the system while that train runs at reduced speed.

What's the max speed of an Acela with the tilt mechanism off?

I remember riding the Sweedish X2000 demo many years(I want to say 1992'ish) ago on a press tour from Philly to Lancaster. They turned off one car so we could see/feel the difference. It was significant. Especially watching the floor in relation to the car ahead of us that was actually tilting. But I don't know to what extent the adjusted the speed.

This post has been edited by PHL: Nov 22 2006, 10:58 AM

[KevinKorell]

That is certainly not good news. I feared something like this could happen, and I only hope it does not result in them pulling the fleet out of service once again and bringing back Metroliners, as in the spring and summer of 2005.

[BillMagee]

The tilt mechanism is a comfort issue, not a safety issue. An Acela with a disabled tilt should be able to run as fast as an Amfleet and would only be penalized over operable tilt mode on curves. Tilt issues should not threaten the Acela operation.

[EvergreenRailfan]

What caused the failure of the tilting system? THe Acela Express uses a different tilting mechanism than the Talgo? Which system is better?

[AlanB]

The tilt mechanism is a comfort issue, not a safety issue. An Acela with a disabled tilt should be able to run as fast as an Amfleet and would only be penalized over operable tilt mode on curves. Tilt issues should not threaten the Acela operation.

Agreed, I've even been on an Acela where tilt failed out of Back Bay. We just didn't hit 150 on those two short streches. Otherwise we ran normally and were only a minute or two late getting into New Haven. I think, but am not positive that we did 135 MPH on the 150 stretches, but maybe we were limited to 125 MPH.

As long as the tilt fails with the car in a normal upright postion it should not be any cause for alarm. If it failed with the train tilted, that might force the train out of service until it could be fixed. But this isn't the first time tilt has failed and I'm sure it won't be the last.

[steve4031]

I'm glad I read this. I was just exploring the idea of an acela trip in two weeks. I hope they don't pull them.

[AlanB]

What caused the failure of the tilting system? THe Acela Express uses a different tilting mechanism than the Talgo? Which system is better?

There are many things that could cause the mechinism to fail, but without word from Amtrak we'll probably never know and I doubt that they'll tell us, unless it becomes a fleet wide problem.

The Acela mechinism is an active system where by computers decide when and how much tilt to apply. Then motors within each car tilt the car accordingly.

Talgos use a passive tilt that relies on gravity and inertia to tilt the car. There are less moving parts this way, but your tilt motion tends to be more haphazard and not as even as what one feels on an Acela. Overall I'd probably say that the active system is better, but it's also probably more prone to failure and more expensive to maintain.

[KevinKorell]

My concern is with, say, that businessperson wearing formal clothes on his or her way to a meeting. They are served a soft drink in First Class. Tilt fails a curve at 150 mph, soft drink spills onto the person, damaging their dry-clean clothing. Customer is rightfully upset.

If the tilt fails in one car, that one car cannot be bad ordered and removed. A fixed consist has to be totally removed from service until the offending car is repaired.

We're talking about keeping schedules here as well. While 150 mph vs 135 or 125 will not result in a lot of minutes lost, Acela does sell itself as an alternative to air travel, and some may consider those minutes precious if a particular train cannot live up to its 150 mph billing on the stretches where it is allowed.

On the positive side, there is probably enough dwell time in New York City southbound to negate the few minutes lost by the forced slower speeds in New England. Going northbound, we know the timetable to be well padded into the three Boston stations, so the time lost should not be noticed.

[jis]

My concern is with, say, that businessperson wearing formal clothes on his or her way to a meeting. They are served a soft drink in First Class. Tilt fails a curve at 150 mph, soft drink spills onto the person, damaging their dry-clean clothing. Customer is rightfully upset.

If the tilt fails in one car, that one car cannot be bad ordered and removed. A fixed consist has to be totally removed from service until the offending car is repaired.

We're talking about keeping schedules here as well. While 150 mph vs 135 or 125 will not result in a lot of minutes lost, Acela does sell itself as an alternative to air travel, and some may consider those minutes precious if a particular train cannot live up to its 150 mph billing on the stretches where it is allowed.

On the positive side, there is probably enough dwell time in New York City southbound to negate the few minutes lost by the forced slower speeds in New England. Going northbound, we know the timetable to be well padded into the three Boston stations, so the time lost should not be noticed.

Several point....

1. At least on one trip from Boston to NY by Acela that I was on, for some reason the tilt mechanism was never turned on, and the train managed to arrive on time in NY. Admittedly it had a very clear sailing all through so none of the padding was necessary to keep on time.

2. The tilt is a comfort issue, not a safety issue. They can run even at 150mph without the tilt.

3. The tilt feature has proved to be one of the lower ROI features IMHO. The weight of the Acela cars makes the cars not rock-solid steady on their suspension (when compared to TGV or ICE) so the behavior of the tilt system is not as clean as it could be (say as it was seen on the X2000) Would probably have been better to spend the money on raising the speed by 5 mph of as many miles as possible of say below 40mph track say on the Hell gate line or between South Station and Ruggles for example.

4. Anybody who worries about a few minutes delay in any Amtrak service needs to change his psych meds and get a new shrink.

[ICGsteve]

If this failure has never happened before then the timing of Amtrak taking over Acela maintenance could prove to be an indicator of the cause of the failure. Is this a gyroscope system? If so we must consider that these components need regular servicing.