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Date: 07/30/20 12:51
Talgo speeds
Author: swingnose

Looks like BNSF will allow Amtrak cascades trains operating with horizon/amfleet equipment to observe posted Talgo speeds and operate with PTC in Tilt train mode.

Anyone have any more info or details on this?

Posted from iPhone



Date: 07/30/20 13:30
Re: Talgo speeds
Author: TAW

swingnose Wrote:
-------------------------------------------------------
> Looks like BNSF will allow Amtrak cascades trains
> operating with horizon/amfleet equipment to
> observe posted Talgo speeds and operate with PTC
> in Tilt train mode.
>
> Anyone have any more info or details on this?
>

I don't, however:

Cliffs Notes preliminary - Cant deficiency: Also called unbalanced superelevation (unbalance). The calculated speed is determined using the amount of superelevation (outside rail higher than inside rail) in inches. Equilibrium Speed is zero cant deficiency. The superelevation exactly offsets centrifugal force. Even freight train speeds are calculated with two inches of cant deficiency. Conventional passenger train speeds are calculated using three inches of cant deficieicy. That means that the speed is calculated on three inches more superelevation than is physically there.  If there is two inches of superelevation in the curve, the passenger speed would be higher as if there was five inches.

More than three inches of cant deficiency must be authorized by FRA specifically for each type of equipment. The testing involves static testing, tilting the track to the point that the high side wheels begin to unload (just below overturning). There is also active testing to see how the equipment reacts when operating at higher cant deficiency. Tilting is for passenger comfort, but tilting train speeds are also based on safely negotiating the curve (which is influenced by center of gravity). The safe maximum Talgo speed for the famous DuPont train wreck curve (for the Talgo train only, not the engines) is 44 mph. The speed limit is 30.

I have heard that Amfleet and Horizon cars have been authorized for five inches of can't deficiency. That would probably be the upper limit of cant deficiency for these cars. Talgo speed is five inches cant deficiency. The train is capable of more than that, but it has never been allowed. The problem that prohibited more in the initial testing was the F59, the F40 cab car, and the condition of some of the BN track. FRA allowed allowed six inches, but BN only allowed five inches to give them some track condition leeway. If tilting trains are not used, running time will never get better than it is now.

TAW



Date: 07/30/20 13:42
Re: Talgo speeds
Author: symph1

Thank you for this clear and informative post.



Date: 07/30/20 17:28
Re: Talgo speeds
Author: GREENGROCER

Hi All I see that Cascades # 500 past the Chehalis railcam at 09:50 today had Talgo cars including the Towmater. Cheers Greengrocer



Date: 07/30/20 22:39
Re: Talgo speeds
Author: Macster

swingnose Wrote:
-------------------------------------------------------
> Looks like BNSF will allow Amtrak cascades trains
> operating with horizon/amfleet equipment to
> observe posted Talgo speeds and operate with PTC
> in Tilt train mode.
>
> Anyone have any more info or details on this?
>
> Posted from iPhone

It was in our GTB's the recently..



Date: 07/31/20 08:01
Re: Talgo speeds
Author: abyler

TAW Wrote:
-------------------------------------------------------
> I have heard that Amfleet and Horizon cars have
> been authorized for five inches of cant
> deficiency. That would probably be the upper limit

That's correct. Amtrak allows operation at 5" cant deficiency for trains consisting of Capitoliner Cab Cars, Amfleet and Horizon cars and for P32, P40, and P42 diesel engines.



Date: 08/03/20 07:17
Re: Talgo speeds
Author: RRTom

TAW Wrote:
The testing involves static testing,
> tilting the track to the point that the high side
> wheels begin to unload (just below overturning).

I think you mean tilting the carbody.



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