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Dual Mode AC / Diesel Electrics for NJ Transit and Montreal

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Dual Mode AC / Diesel Electrics for NJ Transit and Montreal
Posted by jgilber0 on Monday, July 30, 2007 5:36 PM

Back in late May 2007, Trains NewsWire reported that Montreal's commuter agency and NJ Transit "have issued a request for proposals from builders to design, build, test and deliver dual-mode locomotives that can operate using diesel or electric power. The deadline for proposals is July 20."

 http://www.trains.com/trn/default.aspx?c=a&id=1950

From Railway Age, April 1999:

"NJ Transit Rail Operations General Manager Bob Randall says the agency is also investigating acquisition of 20 to 30 "electric-diesel" locomotives that could operate under their own power in non-electrified territory and then switch to overhead a.c. catenary. Such a locomotive, combined with a double-deck car, could be used to provide one-seat service, for example, on the North Jersey Coast and Raritan Valley lines. No such locomotive has ever been built, though the concept has been talked about for years. The feasibility, Randall says, would be limited by two factors. One is weight, which would be much higher than a conventional diesel/third-rail dual-mode due to the requirement for rectifiers and transformers to convert 12.5 kV or 25 kV a.c. into 750 kV for traction motors in addition to a full-size diesel prime-mover. The excess weight could limit top speed to around 80 mph, 20-30 mph slower than what NJ Transit's ALP44 electrics are allowed to operate at on the Northeast Corridor. The other factor is the cost of producing such a highly specialized, limited-application design in small quantities."

 http://findarticles.com/p/articles/mi_m1215/is_4_200/ai_54501488

Did anyone respond to the request for proposals?

Can anybody explain why NJ Transit is interested in dual mode AC / Diesel locomotives for their commuter operations into Penn Station New York?  This seems like a very expensive, heavy, and difficult integration of disparate systems.  I have visions of something big and ungainly like GM1976 or an E44 if they ever actually did make the concept work.

It seems like dual mode DC / Diesel locomotives would make more sense.  This is how Amtrak handled the same issue in the 1990s for service to Albany and points west out of Penn Station.

Wouldn't it be a lot less expensive to equip the trains with a standard diesel on one end, and an electric on the other, and set up push-pull operations?

Thoughts?  Comments?  Answers?

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Posted by JonathanS on Tuesday, July 31, 2007 8:24 AM

Amtrak used dual mode DC/diesel because 600 VDC third rail was available.  For the services that NJ Transit proposes third rail is not available but overhead 11,000 VAC is.  This is also true in Montreal and in Philadelphia.

Having the diesel locomotive at one end of the train with an electric locomotive on the other would be very inconvenient at least in one direction.  When the train reached the tunnels the diesel would need to be shut down.  If it happened to be at the other end of the train the engineer would need to stop the train, walk the length, stop the engine, walk back to the juice jack and continue on with the run.

I know that New Haven and Metro North let the FL9s idle in GCT.  They were not supposed to and at times the fumes were awful.  The ex PRR tubes under the Hudson, the Montreal tunnel and the Philadelphia commuter tunnel do not have the amount of ventilation present in GCT.  Diesel fumes, even from idling locomotives, in those tunnels would be overpowering.

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Posted by CSSHEGEWISCH on Tuesday, July 31, 2007 10:18 AM

The minimal ventilation in the Hudson River and East River tunnels is the reason that PRR/PC/CR kept the original third rail in place after the AC electrification was installed in the 1930's.  Until about 1969, PRR/PC kept a third-rail DD1 on the roster to handle the wire train when maintenance on the catenary was required.  PC replaced the DD1 with an ex-NYC T-motor, also third-rail equipped.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by jgilber0 on Tuesday, July 31, 2007 11:31 AM

Thanks Jonathan and Paul.

Does the third rail still exist in Hudson River tunnels?  If it does, then the dual mode DC / Diesels like those owned by Metro North should work.  I bet that would save a lot of money if NJ Transit went to a proven design like the Metro-North P32AC-DM.

If not, it still seems like it would be easier to figure out a way to remotely shut down a diesel rather than ordering a whole new type of locomotive.  Even if that can't be done, why not just operate the diesel on the east end and place the electric on the west end?  If the locomotives were MU'ed through the train, the engineer could transition to electric power (and push mode) on the fly from the cab of the diesel.  Or am I oversimplifying? 

Thoughts?

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Posted by CSSHEGEWISCH on Wednesday, August 1, 2007 10:38 AM

One-seat service on the North Jersey Coast line (former New York & Long Branch) existed for years, it just included an engine change at South Amboy.  The overhead was extended in the late 1980's to Long Branch and through service from Penn Station to Bay Head was discontinued about that time.  There are through trains that run to Bay Head but they originate at Hoboken.

Dual-mode has proven to be practicable in limited situations but it is expensive.

The daily commute is part of everyday life but I get two rides a day out of it. Paul

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