Passenger Trains > Metrolink new cars and conversions

The new issue of Railway Age states that Metrolink will receive 107 new Bi Level cars. It also says that Metrolink will retrofit the current cars with energy absorbing push back couplers. It goes on to say that the current cab cars will be converted to trailers.

Anybody know what cars Metrolink is ordering?

...
Foamer

Here is a link to the new car image: http://www.trainorders.com/images2/view.php?335289

Todd Clark
Canyon Country, CA
Trainorders.com

> energy absorbing push back couplers ???

That's a new one to me. Help, please.

I believe passenger cars and most freight cars have had these couplers for last 30 or so years

Jaap Wrote:
-------------------------------------------------------
> I believe passenger cars and most freight cars
> have had these couplers for last 30 or so years

Thanks, now I'm really feeling stupid.

Not at all, actually, at least in the US. These couplers function like normal couplers until a very large buff force (>800,000 lbs) is loaded onto the coupler, at which time it shears or pushes back into the draft pocket, deforming the coupler unit in a calculated manner and absorbing energy. This allows the car ends to come together, transferring the buff load to the primary carbody structure. This is all part of the FRA's Crash Energy Management research. The Metrolink application will be the first on a US commuter or passenger railroad, at least on a large scale. Light rail vehicles typically use pushback couplers, but they're much smaller in size and energy absorbed. I've never heard of it in a freight application, and it really doesn't make sense on a freight car, as the point is to prevent massive carshell deformation and collapse like we've seen on some spectacular accidents recently. The cushion underframe and draft gear commonly used on freight cars is very different in nature and function, as it deforms elastically and springs back, whereas a pushback coupler destroys itself during the pushback.

Hope that helps.

Jaap Wrote:
-------------------------------------------------------
> I believe passenger cars and most freight cars
> have had these couplers for last 30 or so years

stevedavis Wrote:
-------------------------------------------------------
> Not at all, actually, at least in the US. These
> couplers function like normal couplers until a
> very large buff force (>800,000 lbs) is loaded
> onto the coupler, at which time it shears or
> pushes back into the draft pocket, deforming the
> coupler unit in a calculated manner and absorbing
> energy. This allows the car ends to come
> together, transferring the buff load to the
> primary carbody structure. This is all part of
> the FRA's Crash Energy Management research. The
> Metrolink application will be the first on a US
> commuter or passenger railroad, at least on a
> large scale. Light rail vehicles typically use
> pushback couplers, but they're much smaller in
> size and energy absorbed. I've never heard of it
> in a freight application, and it really doesn't
> make sense on a freight car, as the point is to
> prevent massive carshell deformation and collapse
> like we've seen on some spectacular accidents
> recently. The cushion underframe and draft gear
> commonly used on freight cars is very different in
> nature and function, as it deforms elastically and
> springs back, whereas a pushback coupler destroys
> itself during the pushback.
>

If the pushback coupler destroy's itself as it absorbs collision energy, is it replaceable in the field? Assuming it does its job and sacrifices itself and protects the car itself, what is it going to take to move the damaged car to a repair facility?

Greg

Greg Ramsey
Las Vegas, NV

I think you may have missed the point that this would be a very serious collision and how to move whats left afterward is not exactly the highest priority. The draft pocket / coupler assembly deforms so the car ends can come together evenly and the remaining forces transferred to the car body in the way they can best handle them. They in turn deform depending on the force of the impact. The point is to absorb as much force of the impact as possible and save the lives of the occupants. The car will likely be unrepairable and may or may not be moveable on its own wheels after such a collision so how to couple to whats left isn't much of an issue.

I suppose if you have a collision with impact greater than that needed to destroy the coupler pocket but not so great as to make the car unmovable then maybe the coupler at the other end is still good or you resort to chains etc. Either way it's a special move and not something you just ship off for repair in the local freight.

The current standards for pushback couplers include the provision for retaining some draft strength so that equipment with deployed coupler units can still be hauled back to a maintenance facility (assuming the equipment is still road-worthy).

filmteknik Wrote:
-------------------------------------------------------
> I think you may have missed the point that this
> would be a very serious collision and how to move
> whats left afterward is not exactly the highest
> priority. The draft pocket / coupler assembly
> deforms so the car ends can come together evenly
> and the remaining forces transferred to the car
> body in the way they can best handle them. They
> in turn deform depending on the force of the
> impact. The point is to absorb as much force of
> the impact as possible and save the lives of the
> occupants. The car will likely be unrepairable
> and may or may not be moveable on its own wheels
> after such a collision so how to couple to whats
> left isn't much of an issue.
>
> I suppose if you have a collision with impact
> greater than that needed to destroy the coupler
> pocket but not so great as to make the car
> unmovable then maybe the coupler at the other end
> is still good or you resort to chains etc. Either
> way it's a special move and not something you just
> ship off for repair in the local freight.