by dowlingm
Aren't some of those already earmarked for SEPTA to bridge them until they get their new ones?
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Moderators: mtuandrew, therock, Robert Paniagua
dowlingm wrote:Aren't some of those already earmarked for SEPTA to bridge them until they get their new ones?Not decided yet. Amtrak hasn't made any decisions on long-term leases for the Remans, so these random appearances on MARC trains are the extent of it for now. 6 to SEPTA was the rumor quoted by AMTK employees on the forums, but that was awhile ago and it's a fluid rumor. Sprinters gotta have the kinks worked out before it's prudent to let them start taking 'dibs' on formal leasers, so whether there's been any discussions with SEPTA or more or less agreed-upon number of leasers...they obviously can't say anything, transact anything, or pin a calendar date on such a transaction until Amtrak's more or less finished the fleet replacement to its own satisfaction. And I'm sure that's well-understood by SEPTA.
Backshophoss wrote:At times,Amtrak has "borrowed" MARC's Hippo's for service across the NEC,it might be in Amtrak's interest to Lend/LeaseYep #925 (AMTK AEM-7AC) was on a MARC consist today.
some the "stored serviceable" AEM-7's(or the stored Hippo's) to MARC to get the "Rush Hour" trains on the motors
instead of the MP-36's that can't keep up.
farecard wrote:Which, if any of the new electrics out there are AC? When I was last reading up on the topic, it looked like the vendors were still (Edison would be proud....) pushing DC-motored units....All of them.
F-line to Dudley via Park wrote:
Only places you still see DC-anything being bought new is freight diesels because that's still optimal traction performance for some freight needs. But even that market is shrinking big now that Tier 4 air quality standards are squeezing them out for AC's.
.....
It's an AC traction world now. And on the electrics side parts availability for DC's is a bigger constraint than actually finding someone offering them in a product catalog. It's not hard to find replacement parts for an AEM-7AC; the AC guts they were remanufactured with are pretty generic. It's brutally difficult to find parts for an AEM-7DC; Amtrak was having a lot of trouble near the end scraping up bits and pieces to keep their fleet running.
mtuandrew wrote:I'm coming into this discussion late, so sorry if this has been asked & answered, but...NJT has to substitute its dual-mode ALP-45DP's it has too few all-electrics to go around. They're in no position to lease out their ALP-46's. It's pretty much the AEM-7AC's as short-term reliable power available in the very near future. The "reliable" part being why MARC--or anyone--will never ever look at AMTK's stored HHP-8's. That would just be masochism.
Let's say MARC is bluffing Amtrak about converting to full diesels, and wants some electrics to hold it over before they go shopping for new motors. So far, this thread is talking up AEM-7ACs for good reason. What else is out there? Does NJT have any spare ALP-46 1st-gens it could lease to MARC?
(I'd kind of love to see ALP-44s rebuilt in the spirit of the AEM-7AC rebuilds, but this is both unrealistic and out of the scope of this thread.)
farecard wrote:Thinking back, it must have been a freight diesel thread I read not an electric one. I still don't grasp why an AC motor delivers less traction than a DC one; if it's a weight difference, add ballast. And I agree re: the electronics availability. But the big issue is no %&$%^&$ DC motors to maintain.Short answer: it's a power curve issue.
mtuandrew wrote:Well, series-wound DC motors provide 0-rpm torque. That's how your car starter works. I guess locomotive motors would also be, to a major extent.
Short answer: it's a power curve issue.
Long answer: DC motors provide maximum torque at 0 rpm, while AC motors provide max torque at a higher range (I forget exactly what though.) It'd be perfect, except that you burn up your DC motors' brushes and have to limit the power. AC doesn't have that limitation, so you can start at Notch 8 and dump as many amperes into the motors as your cooling system can handle.
F-line: I'm looking forward to the HHP-8 line by Gillette. :P
farecard wrote:The typical phrase I've seen with AC motor specs is "3-phase; 4-pole"mtuandrew wrote:Well, series-wound DC motors provide 0-rpm torque. That's how your car starter works. I guess locomotive motors would also be, to a major extent.
Short answer: it's a power curve issue.
Long answer: DC motors provide maximum torque at 0 rpm, while AC motors provide max torque at a higher range (I forget exactly what though.) It'd be perfect, except that you burn up your DC motors' brushes and have to limit the power. AC doesn't have that limitation, so you can start at Notch 8 and dump as many amperes into the motors as your cooling system can handle.
F-line: I'm looking forward to the HHP-8 line by Gillette.
Are the AC motors geared down or many-poled?
Fan Railer wrote: The typical phrase I've seen with AC motor specs is "3-phase; 4-pole"