Multiple Units as Hauled Stock/Trailers

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  • Member since
    February, 2018
  • 20 posts
Multiple Units as Hauled Stock/Trailers
Posted by RailfanGXY on Saturday, February 17, 2018 7:02 PM

I've been on a bit of an MU kick as of late, and a thought occured to me for potentially operating dividing/through passenger trains. I understand that most current MU's use WABCO N-Type multifunction couplers, but it could be possible for an AAR coupler to be fitted in a "swingdrop" position like on certain British passenger cars. I've also seen numerous instances of older MU trains being towed by a conventional locomotive, yet seemed to be hauled stock rather than "dead units". Think of it like a train of Arrows running on the old New York & Long Branch Railroad, but rather than having the passengers transfer to unpowered passenger cars, a fully diesel-powered ALP-45. This removes the process of changing engines at electrification endpoints (just adding a locomotive or letting it run off), and still allows for the benefits of EMU power where there's third rail/catenary.

Is it possible that MU consists like Silverliners, Arrows, and Metropolitans could be used as passenger cars nowadays, pulled by a conventional locomotive? If so, would it also be possible to fit a swingdrop WABCO N around an AAR coupler and connect it to an loco's electrical plant?

 

Also, can someone please explain what exactly an MU trailer is?

  • Member since
    February, 2018
  • 20 posts
Posted by RailfanGXY on Saturday, February 17, 2018 7:05 PM

RailfanGXY

I've been on a bit of an MU kick as of late, and a thought occured to me for potentially operating dividing/through passenger trains. I understand that most current MU's use WABCO N-Type multifunction couplers, but it could be possible for an AAR coupler to be fitted in a "swingdrop" position like on certain British passenger cars. I've also seen numerous instances of older MU trains being towed by a conventional locomotive, yet seemed to be hauled stock rather than "dead units". Think of it like a train of Arrows running on the old New York & Long Branch Railroad, but rather than having the passengers transfer to unpowered passenger cars, a fully diesel-powered ALP-45. This removes the process of changing engines at electrification endpoints (just adding a locomotive or letting it run off), and still allows for the benefits of EMU power where there's third rail/catenary.

Is it possible that MU consists like Silverliners, Arrows, and Metropolitans could be used as passenger cars nowadays, pulled by a conventional locomotive? If so, would it also be possible to fit a swingdrop WABCO N around an AAR coupler and connect it to an loco's electrical plant?

 

Also, can someone please explain what exactly an MU trailer is?

 

 

My mistake, I put this in the wrong forum... I'm so sorry!

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Posted by Overmod on Sunday, February 18, 2018 9:45 AM

Not in the wrong forum, just not the right subforum (this one being for trainwatching guides).  You can PM one of the mods to move it to a better subforum or post it again.

There is at least one famous use of MU equipment in the way you describe (although it predates the use of 'modern' integrated couplers): the New York Central famously operated trains of older MUs north of the end of third rail at Harmon, all the way to Poughkeepsie, using Hudson locomotives with conventional AAR couplers and no HEP.  During the SEPTA strike in the mid-Seventies, trains of Reading steel MUs were pulled by GG1s (with one pan raised in the consist for auxiliaries and lighting but not motoring)

In the United States, most arrangements for 'towing' equipment with various kinds of 'transit' coupler are made with adapters, not a separate fixed coupler on a swing or drop arrangement.  

The use of modern MUs as trains did not catch on here for a variety of reasons.  Most were designed with full air conditioning and sealed windows (with the somewhat sensible assumption that traction levels of amperage would always be available when running) and fancy brake systems with things like  proportional load control.  A relatively high 'weight penalty' may exist for the various components of the propulsion system.  The general solution in North America for situations involving 'towed MUs' has generally been to use lightweight unpowered stock and either use a dual-power locomotive or run 'top and tail' with an electric on one end and a diesel on the other (see the Atlantic City Express).

Note that in at least one instance a self-propelled RDC was adapted to be towed behind an MU consist (!) to facilitate operation into Manhattan where diesel operation was not allowed.  (This was as I recall the modern version of the Poughkeepsie service formerly done with MU stock.)

Tourist roads sometimes make use of MU cars as relatively cheap stock.  But I don't know of any offhand that use equipment originally designed with sophisticated couplers, and if they did I would expect them just to replace the coupler and draft gear with something 'standard' and rig up more-or-less homemade power arrangements.

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Posted by daveklepper on Tuesday, February 20, 2018 11:31 AM

There may have been mus hauled to Pp9ughkeepsie at one time or another, but for many years only the Peeksklill trains did this regularly with the Poughkeepsie trains using downgraded long-distance coaches and T and then P-motors south of Harmon.  Hudsons were rarely used on the Peekskill trains because few or any had lighting generators compatible with the mu-car lights.  Pacifics did.  There were mu-cars equipped for steam heat, but not with axle generators.  This is what I remember from about 70 years ago.

I was around when the Budd car was hauled into Grand Central.

Amtrak for a while used SPVs on the back of a Boston train from Penn Sta. to New Haven, which could then run on their own power to Springfield.  SPV's had connections for head-end power compatible with Amfleet.

  • Member since
    February, 2018
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Posted by RailfanGXY on Tuesday, February 20, 2018 6:15 PM

Heheh. Being essentially a motorized Amfleet, that would make sense. Shame they didn't run well under their own power. And if they were used on NEC (I think it was at that point?) trains...the heck was their top speed?

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Posted by Overmod on Tuesday, February 20, 2018 9:20 PM

The SPVs ran fine under their own power -- it was the detail design of the little 4-cylinder APU that kept the controls working, and the decision not to gear all the wheel sets together, that were the principal reasons they became Seldom Powered Vehicles

They were designed for service up to 120mph in sets of 6, with the sort of nose-cone streamlining that was supposed to evoke 'high speed train' in that era.  Had they been run with all eight wheels driven, I think there was sufficient engine power to get even flat-ended trains to reasonably high speed.

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