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Nostalgia & History > Why American Cars are so Heavy


Date: 01/16/11 20:53
Why American Cars are so Heavy
Author: ats90mph

A bnsfbob indicated in this thread: http://www.trainorders.com/discussion/read.php?11,2368699 indicated that American Lightweight cars are heavier than they need to be in order to resist forces in a derailment. The reason for the requirement was due to older "Heavyweight" cars in the same consist of "Lightweight" cars. The first accident involving lightweight cars was an accident on the Southern Pacific in 1938. The Tortuga, Calif (near Niland) wreck was a head on collision that was caused when a Brakeman opened a switch in front of an oncoming train. Train 44 Eastbound, The Californian was in the siding when Westbound Train 5 The Argonaut, struck the standing train in the siding. Both trains had brand new lightweight cars with a mix of traditional heavyweights. The lightweights which consisted of Cor-Ten steel construction damaged when the heavyweight cars distributed their energy into the lightweights, the result was extraordinary breaches into the carbody of the lightweights. The cars included baggage and even an Articulated Coach that was on #44. Since this was the first wreck involving lightweights some were surprised with the results. After the rearender in Naperville, Ill in 1946, the government required "lightweight" cars to be built not so light. However this whole issue is moot now since there are very few instances where "Lightweight" and "Heavyweight" are mixed anymore.

Here are some photos of the 1938 wreck in Tortuga, showing what happened to the lightweights, the whole ICC report can be found on: http://ntl1.specialcollection.net/scripts/ws.dll?websearch&site=dot_railroads


1. Showing the brand new Articulated Coach that was the 3rd car in on train 44, Car 2418/19 was built by Pullman-Standard in May 1937

2. Close up of the damaged end of the 2418, the mate 2419 was not damaged. You can see the Collision Posts and even the Center Sill bypassed by the crash

3. SP 2438 was the fourth car on the Argonaut, showing considerable damage



Edited 2 time(s). Last edit at 01/16/11 21:19 by ats90mph.








Date: 01/16/11 21:00
Re: Why American Cars are so Heavy
Author: ats90mph

4. Showing the two engines after they butted heads at 40MPH

5. How everything ended up after the meet

6. How the Heavyweights fared








Date: 01/16/11 21:11
Re: Why American Cars are so Heavy
Author: lwilton

In theory with better force analysis tools available these days, and the now slightly lighter "lightweight" cars, it would probably be possible to build a generation of significantly lighter cars that could still survive mixed-consist impacts of various types. Of course there are probably legacy FRA laws that would prevent the use of any such designs, continuing to make passenger rail far more wasteful of power than it really should be.

It should also be possible to make dedicated-consist trains that don't mix with older cars and make them even lighter; say something like a 5-unit articulated passenger car or DMU unit built along the general lines of the articulated car carriers. You still need to put mass and stiffness where it is necessary for safety, and you need to think thru crash scenarios to figure out where that needs to be. But it is just basic engineering and could in theory be done these days, if laws do not prevent it.

(For instance: design an articulated car so that it is almost guaranteed to accordion-fold in a major crash, and make the bodies stiff enough to not twist. That would make a rollover fairly difficult and greatly reduce the chance of telescoping. Then your major worries become crashes in tunnels and on mountain sides. End stiffening could probably help in tunnels, and hopefully major collisions are rare on mountain sides.)



Edited 1 time(s). Last edit at 01/16/11 21:14 by lwilton.



Date: 01/16/11 21:26
Re: Why American Cars are so Heavy
Author: ats90mph

lwilton Wrote:
-------------------------------------------------------
> In theory with better force analysis tools
> available these days, and the now slightly lighter
> "lightweight" cars, it would probably be possible
> to build a generation of significantly lighter
> cars that could still survive mixed-consist
> impacts of various types. Of course there are
> probably legacy FRA laws that would prevent the
> use of any such designs, continuing to make
> passenger rail far more wasteful of power than it
> really should be.
>
> It should also be possible to make
> dedicated-consist trains that don't mix with older
> cars and make them even lighter; say something
> like a 5-unit articulated passenger car or DMU
> unit built along the general lines of the
> articulated car carriers. You still need to put
> mass and stiffness where it is necessary for
> safety, and you need to think thru crash scenarios
> to figure out where that needs to be. But it is
> just basic engineering and could in theory be done
> these days, if laws do not prevent it.
>
> (For instance: design an articulated car so that
> it is almost guaranteed to accordion-fold in a
> major crash, and make the bodies stiff enough to
> not twist. That would make a rollover fairly
> difficult and greatly reduce the chance of
> telescoping. Then your major worries become
> crashes in tunnels and on mountain sides. End
> stiffening could probably help in tunnels, and
> hopefully major collisions are rare on mountain
> sides.)

This is exactly why DMU's are not popular, because the FRA does not think they could handle a dance with a freight or standard passenger train well enough.



Date: 01/17/11 00:07
Re: Why American Cars are so Heavy
Author: up833

The Talgo trains used on the Cascade trains in WA and OR are dedicated cars and cannot mix with other types of cars. They have been used for a number of years so its not a new concept.
Roger Beckett



Date: 01/17/11 02:13
Re: Why American Cars are so Heavy
Author: Evan_Werkema

up833 Wrote:

> The Talgo trains used on the Cascade trains in WA
> and OR are dedicated cars and cannot mix with
> other types of cars. They have been used for a
> number of years so its not a new concept.

Aren't they also operating under a waiver from the crush-strength regulation?



Date: 01/17/11 08:11
Re: Why American Cars are so Heavy
Author: TAW

Evan_Werkema Wrote:
-------------------------------------------------------
> up833 Wrote:
>
> > The Talgo trains used on the Cascade trains in
> WA
> > and OR are dedicated cars and cannot mix with
> > other types of cars. They have been used for a
> > number of years so its not a new concept.
>
> Aren't they also operating under a waiver from the
> crush-strength regulation?


mmm....not really. They were designed before the current regulations were in effect. There was a lot of politics involved. Engineering studies proved that they could withstand the required forces of the new regulations but FRA insisted that compliance required physical testing, which would destroy the equipment. There was a big battle, and a compromise of sorts was reached that required some relatively minor fixes and required an engine or cab car on both ends of the train. The "grandfathering" also provided that the existing trains could not leave the Eugene - Vancouver BC corridor. It's good to know that this is the safest railroad in the US!

Meanwhile, back at the ranch, not long after being put in service, 795 (later to become 509) did a real quick 60 to 0 when it hit a 12 foot deep mudslide at Castle Rock. The train stayed on the railroad and injuries were a couple of passengers who happened to be standing and fell down when the train stopped and they didn't. Over in Spain, an operator screwed up and let a (Talgo) passenger train into a (manual) block occupied by an opposing freight train. They hit at track speed. The freight engine vaulted over the head end of the passenger train and landed on top a couple of cars back. There was a fire below the freight unit, promoted by the diesel fuel leaking down onto the cars below. The fatalities in the wreck were caused by fire, not trauma. The articulated Talgo train derailed and stayed in line with the track. The anecdotal evidence was not sufficient to deter the desire to destroy a train to see how strong it was or restrict them because none were destroyed in testing.
The current version of the equipment has been physically tested at Pueblo and is good to go.

TAW

THOMAS WHITE
MOUNTLAKE TERRACE, WA
Rail Transportation/Train Dispatchi



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