Metro-North car diaphragms

[SouthernRailway]

Definitely an arcane question but I see that Metro-North and NJ Transit both seem to use tube-style diaphragms on their locomotive-hauled passenger cars, with just round rubber tubes around the doorways between cars.

 

Conversely, Amtrak (at least Amfleet, Viewliner and Heritage Fleet, plus North Carolina Amtrak), Trinity Railway Express and other railroads use more traditional diaphrams with metal plates at the ends of the diaphragms, and the diaphragms aren't round.

 

Is there a reason for one vs. the other? Is one the "new" way or the "cheap" way?

 

Thanks.

[gregorygrice]

Definitely an arcane question but I see that Metro-North and NJ Transit both seem to use tube-style diaphragms on their locomotive-hauled passenger cars, with just round rubber tubes around the doorways between cars.

 

Conversely, Amtrak (at least Amfleet, Viewliner and Heritage Fleet, plus North Carolina Amtrak), Trinity Railway Express and other railroads use more traditional diaphrams with metal plates at the ends of the diaphragms, and the diaphragms aren't round.

 

Is there a reason for one vs. the other? Is one the "new" way or the "cheap" way?

 

Thanks.

 

Those are just to prevent the two cars from rubbing against each other and also to close the gap between the cars.

[SouthernRailway]

Sorry, wasn't clear- why are some railroads now using tube-style diaphragms instead of the older ones with metal plates? Weight, safety, cost, etc.? Why the difference?

[metsfan]

On most commuter equipment, they do not leave consists together for extended periods, they are broken apart for inspections, minor repairs & cleaning. Amtrak on the other hand can leave cars coupled together for a week or more at a time. That would be the purely operational reasoning. They often separate cars one at a time to inspect hoses and cables etc as far as i've heard.

 

Also, the stuff on amtrak basically seals in the car ends to each other, people can move from car to car without worrying bout getting rained on or whatnot. To and from sleeping lounge cafe snack cars etc. NJT for example, there's no reason to change cars unless to find a seat, then you sit there & that's it till you exit the train. That would be the purely in service functionality reasoning.

 

If you've noticed, the cab cars often have one solid upside down U shaped diaphragm, while the rest of the cars have a 3 piece type deal. This is because cab cars (generally) do not sit in the consist, but facing "out" away from the locomotive at the end. The one piece is easier to maintain, much more aerodynamic, and on the more often bumped together 3 piece dealies, if one section is damaged you simply replace it. You don't want a hornet nest or such appearing up in there either.

 

Hope that makes sense.

 

- A