Overmod They liked them enough to repeat order them, but I get the impression they use both engines for rapid acceleration rather than high speed and don't make a 'thing' out of idling one of the engines a la genset to save fuel at other times. They're certainly a delight to watch and hear in service, right up there with NJT's locomotives with the Polish-block 710s that even though dressed in a clumsy-looking Vergara clown suit have sound among the best anywhere -- and I say this as a dedicated U34CH fan. Apparently Wabtec has no success selling a 'more hp than needed for PRIIA 125mph in a single carbody' vs. the single-engine larger QSK95 in the Siemens Chargers. Presumably American commuter districts make do with adjusting consists to the lower horsepower; doubleheading MP54s is glorious even on longer trains but it's overkill if you aren't wanting to pay for the acceleration and can't use the full top speed, and tinkering to use only one engine in one of a doubleheaded pair is a waste of much of the added capital costs. [BTW -- can you point me at a copy of the EMD suit that showed the original Siemens Charger design for IDOT wasn't physically capable of meeting the PRIIA spec (by about 2mph as I recall the calculations?) I have this dim, probably incorrect memory that the IDOT QSK95 was supposed to be kept at 1200rpm (with only short-time 'boost') and this was being promoted as making the engines far more reliable than the Cat alternative -- then the production locomotives went to 1800rpm to match the C175s and handily met specs when so 'modified'.]
They liked them enough to repeat order them, but I get the impression they use both engines for rapid acceleration rather than high speed and don't make a 'thing' out of idling one of the engines a la genset to save fuel at other times.
They're certainly a delight to watch and hear in service, right up there with NJT's locomotives with the Polish-block 710s that even though dressed in a clumsy-looking Vergara clown suit have sound among the best anywhere -- and I say this as a dedicated U34CH fan.
Apparently Wabtec has no success selling a 'more hp than needed for PRIIA 125mph in a single carbody' vs. the single-engine larger QSK95 in the Siemens Chargers. Presumably American commuter districts make do with adjusting consists to the lower horsepower; doubleheading MP54s is glorious even on longer trains but it's overkill if you aren't wanting to pay for the acceleration and can't use the full top speed, and tinkering to use only one engine in one of a doubleheaded pair is a waste of much of the added capital costs.
[BTW -- can you point me at a copy of the EMD suit that showed the original Siemens Charger design for IDOT wasn't physically capable of meeting the PRIIA spec (by about 2mph as I recall the calculations?)
I have this dim, probably incorrect memory that the IDOT QSK95 was supposed to be kept at 1200rpm (with only short-time 'boost') and this was being promoted as making the engines far more reliable than the Cat alternative -- then the production locomotives went to 1800rpm to match the C175s and handily met specs when so 'modified'.]
Here's the only link I could find to the lawsuit but you need to join to see it all:
https://www.scribd.com/document/205490917/HSR-IDOT-Multi-State-Procurement-Protest-Feb-2014-Original
I wasn't involved although I was a contractor at EMD at that time. I'd be really surprised if they were limiting the engine to 1200 rpm.
Not sure what NJT locos you are referring to - the PL42AC's? Those were EMD supplied engine/alternators to Alstom, who owned the Valencia plant at the time.
Wabtec/MPI's limitation is weight, not to mention lack of a 125 mph truck - I designed the trucks under the HSP46 for MBTA but those are a stretch at 110 mph - I'd never try to use them at 125 mph without disc brakes and with their pedestal primary arrangement, they'd have to run cylindrical profile for any hope of stability.
My interest in the MP54AC is that I did the original equipment layouts for that model while contracting with MPI, before I re-joined EMD in 2010, so wonder how they've worked out.
Dave
Just wondering how these locomotives are performing in service, how many have been delivered, and if they are living up to expectations. I don't see much of anything about them on the RR fan sites I frequent. AFAIK, these have the highest HP of any diesel on 4 axles.
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