by west point
Why can't the 60 Hz be extended to where the present 3rd rail ends ? Cannot recall exactly how all that worked. have not been there since way before Hell Gate was converted to 60 Hz.
Moderators: GirlOnTheTrain, nomis, FL9AC, Jeff Smith
west point wrote: ↑Thu Jul 22, 2021 3:07 amWhy can't the 60 Hz be extended to where the present 3rd rail ends ? Cannot recall exactly how all that worked. have not been there since way before Hell Gate was converted to 60 Hz.The break between the NH and PRR systems was moved south at some point, and now Amtrak has the small 60hz system in NYC that is mostly ex-New Haven with a bit of PRR south to the phase break to 25hz.
Jeff Smith wrote: ↑Fri Aug 06, 2021 12:22 pmHowever, it looks like they're going to run a pretty hefty schedule, which would require a pretty hefty fleet purchase, both motive power and coaches, just for the one line. Now, they may have to do that anyway, because I doubt the M8 fleet is sufficient to cover both NYP and GCT.The challenge in NYC is that most of the equipment is bespoke, so you have to figure out what's going to run where and then you have the MTA/CDOT ownership issue. If there were extra M-8s after buying push-pull cars for Penn Access, technically they'd be perfectly happy running on the Harlem or Hudson Lines, but that would require MTA to buy out CDOT's ownership of x number of cars (and then pool them).
The 8's weren't built with the equipment necessary for the overhead power change. IIRC, it was due to the weight penalty. So they settled on the over/under shoes. It still provides a good amount of flexibility, but they won't be capable of through running. I'd imagine once ESA is done, a lot of space will be freed up in the LIRR yards on the west side, or if they dead-head back to New Rochelle.Yup, weight for the Park Ave Viaduct. I don't know if some M-8s could be retrofitted, but building an EMU with 25/60hz overhead capability isn't that hard. Through running is just far more efficient than terminal operations. There is no practical way to through run with LIRR, it would be a waste to have M-8 style cars with 25hz transformers, as they would be very expensive, heavy, and require more maintenance, but for the New Haven Line, where there is an easy solution, it makes total sense.
The break was moved south because MNRR retired the old Cos Cob plant and went with commercial power. That left the Hell Gate (Harlem River) line swinging in the breeze.But how did the PRR/NH break end up so far south? Did the New Haven always power the Hell Gate Bridge itself? On second though, it makes logical sense, as the New Haven operated down the Bay Ridge branch, so the break was probably always around present-day GATE.
west point wrote: ↑Fri Aug 06, 2021 9:24 pmIt would be very interesting how much MNRR has saved by going to 60 Hz instead of 25 Hz. The costs of conversion taken in to account.Probably a lot. But the conversion of the PRR system is not analogous to the NH or Reading systems, the former of which has been converted, the latter of which has not. The NH and Reading systems were just split-phase autotransformer systems, they didn't have high voltage transmission. The PRR system is basically it's own power grid, probably the largest or one of the largest in the US when it was built in the 1930's, complete with high voltage transmission and substations.
Then we now have the necessity of dual frequency or other problems going to Penn Station will slightly increase operating cost for that segment? Since Penn is a longer run not as much revenue per operating mile as would expect to be some NYP & GCT ? That with maybe slightly higher operating costs probably not more than 10% ?Other than the increased capital expenditures for the third rail extension and future 25hz capable equipment for through-running, the electricity cost to use the PRR system wouldn't be any more than on the MN system, except for the various agreements on how to account for power cost and rates between Amtrak and commuter railroads versus MN owning their system and selling power to Amtrak. Whatever conversion losses are incurred on the PRR system are probably more than offset by higher power costs in CT anyway. Any loco-hauled electrics that are anywhere in the Northeast are most likely going to be 25hz capable, even ones running on the MBTA, so as to keep compatibility with the whole corridor, and/or to make a single model across multiple agencies.
njtmnrrbuff wrote: ↑Sat Aug 07, 2021 7:33 amI believe that right now, there is presently a surplus of M8s around so probably in the future, there will probably be enough to cover the Penn Station trains. Close spacing between stops on the Hellgate Line will certainly suggest that using M8s as best, although the Sprinters have good acceleration too.I don't know what the actual acceleration numbers look like for EMU vs. push-pull electric, but people often cite the NJT push-pulls as being really slow and adding schedule time over the Arrows. The problem with those, however, is they they often have 10-12 cars with one locomotive, when they should have one locomotive per 6 cars, especially with those heavy MLs. Horsepower wise, 14,000ish HP on a 12 car train is plenty, but I don't know how quickly they can convert that all to tractive effort from a stop versus a 12,000HP EMU set.
ElectricTraction wrote: ↑Thu Aug 26, 2021 10:16 pm The challenge in NYC is that most of the equipment is bespoke, so you have to figure out what's going to run where and then you have the MTA/CDOT ownership issue. If there were extra M-8s after buying push-pull cars for Penn Access, technically they'd be perfectly happy running on the Harlem or Hudson Lines, but that would require MTA to buy out CDOT's ownership of x number of cars (and then pool them).M-8's run on the Harlem Line. I've ridden them. And the CDOT Shoreliners/P32AC-DM's/BL20GH's all operate agnostically in pool service. The equipment isn't captive to CT.