• Commuter Rail Electrification

  • Discussion relating to commuter rail, light rail, and subway operations of the MBTA.
Discussion relating to commuter rail, light rail, and subway operations of the MBTA.

Moderators: sery2831, CRail

  • 182 posts
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  by ElectricTraction
 
BandA wrote: Sun Jul 18, 2021 5:07 pmIs acceleration causing schedule-keeping problems for the T? How much time would be saved for a Worcester, a Fitchburg, or Providence train if they were electric push-pull or DMU or EMU?
Acceleration is the main determinant of how fast commuter rail service is, not top speed. Most commuter services rarely hit MAS, and only for short segments. Thus, fast accelerating EMUs or loco-hauled electric with multiple locomotives will do a lot more than 125mph capable commuter equipment will. Faster commuter service would do little to cannibalize Amtrak Regional in most cases, they are two difference services, and two different markets. NHV-NYP is an exception, the new MN service will likely cannibalize some of the small amount of traffic on that route, but it's probably miniscule, as most already goes to GCT on MN.
CRail wrote: Sun Jul 18, 2021 6:23 pmThere's no argument that electric powered vehicles aren't superior in efficiency and performance for service making frequent stops, the argument is over whether or not the benefits gained are worth the prohibitive infrastructure expense. I've opined repeatedly and maintain my position that electrics are a no brainer on some routes but don't make sense on others.
For the T, everything except the Old Colony and Greenbush lines should be electrified. Part of the issue is excessive cost, which plagues all of our infrastructure. Lower maintenance, faster speeds, lower energy costs, and of course decarbonization are all huge benefits to electric, and are well worth the $2.4M/mi cost for overhead AC electrification. If you start to see figures significantly higher than that, then there are cost problems, and those need to be addressed as such.
BandA wrote: Tue Jul 20, 2021 2:07 amI think batteries will remain impractical except for niches like filling in gaps under bridges, switching engines in covered coach yards, etc. Hydrogen has the fundamental problem that it has to be manufactured from something else, and burning something else is usually cheaper than burning a synthetic fuel.
The idea is that Hydrogen will be produced by renewable energy, but we need to use it way more efficiently than we use diesel today, like with relatively lightweight HMUs on lower density routes. Batteries are not useful for commuter rail at their current energy density and weight, I could see them being useful for freight switching, and in fact such a system was used many decades ago on the Chicago North Shore Line for off-wire freight switching. There are plenty of small yard, terminal, and high density shortline operations where battery switchers would make sense.

Using batteries for going under bridges is rather problematic and the clearance issues should actually be dealt with, not kludged around. I could see mainline freight electrification using locomotives with limited battery range to get in and out of grain loop loaders or intermodal yards, but that's a whole different topic.

Switching to LNG or CNG isn't useful, it's switching one dirty fossil fuel for another.
  by bmvguye39
 
I mentioned batteries and Hydrogen earlier as an alternative because I dont see the heavy electrical infrastructure getting installed along the North Shore anytime soon. While I love trains, I wouldnt want to see that everyday and would actually protest against it. Maybe a third rail option thats ground based if possible? Otherwise, I would be happy with either smaller DMUs or cleaner burning diesels... there have to be other options than overhead cantenary. It cant always be about appeasing the NIMBYs and environmentalists!
  by BandA
 
I miss seeing the trolley wires on the Watertown "A" line, and enjoy seeing the trackless-trolley wires. Although Amtrak 165MPH+ rated catenary is kind of visually disturbing.
  by ElectricTraction
 
bmvguye39 wrote: Thu Jul 22, 2021 12:03 pmI mentioned batteries and Hydrogen earlier as an alternative because I dont see the heavy electrical infrastructure getting installed along the North Shore anytime soon. While I love trains, I wouldnt want to see that everyday and would actually protest against it. Maybe a third rail option thats ground based if possible? Otherwise, I would be happy with either smaller DMUs or cleaner burning diesels... there have to be other options than overhead cantenary. It cant always be about appeasing the NIMBYs and environmentalists!
Third rail is terrible. It's much more expensive to install, much less efficient, and there are serious safety issues with having 770DC where people or animals can walk up to it. The only place that third rail should be installed is LIRR, in order to maintain compatibility with the rest of the system. Any other new electrification should be done with 25kV AC overhead wire.

That sort of NIMBY BS is unfortunately a political reality when sanity can't overrule it, but overhead electrification certainly can be installed in a way that doesn't create too much of a visual footprint, like was done by Amtrak along the Shore Line through a lot of mostly small towns. Appeasing the NIMBYs is when you don't electrify because people complain that it "looks ugly". That's more of a political and educational issue than a technical issue, as modern electrification projects like the Shore Line have mastered the technical methods of minimizing the visual and environmental impacts of electrification while providing a reliable and robust electrification system, largely based on a modernized version of the New Haven railroad's 1914 system.

Lines that are large enough to have frequent service with 5+ car trains should be electrified. Most smaller lines should use DMUs or HMUs with 4 or fewer cars. The exceptions to this dichotomy where diesel push-pull or dual-modes still make sense are long-and-thin lines, either like Old Colony and Greenbush, where they are sharing a single track that limits frequency, or like Port Jervis where diesel trains run a long route from the exurbs into a busy big-city terminal. Some are marginal for electrification like the Hartford Line commuter service, but most of the T should be electrified.
  by west point
 
3rd rail at 600 - 1000 volts are just not available for loco hauled trains. So an ACS-64 pulling 6400 HP or short time 8400 HP = 4413 kW and 6187 kW respectively. which equals O = The Amp pull is 7355 and 10,311 respectively at 600 volts . . There is no 3rd rail shoe(s) that can take that load even at a max of 4 shoes to divide the load.

Now take 25k kV AC Amp loads on the CAT is 176 and 247 respectively single phase.. That only requires 2/o cable air and 4/o interior cable. That is as well only a substation for overhead is about 20 - 25 miles dependent on number of trains in the sections. That is why 3rd rail is a non starter.

Note a 12 car EMU with 500 HP each car adds up to 6000 of an ACS-64 HP. Think an Acela-2 has what HP with both ends working off one PAN.

As an aside some California pols are pushing for the HSR to use 3rd rail. Any guesses ?.
  by ElectricTraction
 
west point wrote: Sat Jul 24, 2021 12:51 am3rd rail at 600 - 1000 volts are just not available for loco hauled trains. So an ACS-64 pulling 6400 HP or short time 8400 HP = 4413 kW and 6187 kW respectively. which equals O = The Amp pull is 7355 and 10,311 respectively at 600 volts . . There is no 3rd rail shoe(s) that can take that load even at a max of 4 shoes to divide the load.
The other issue that the locomotives have, other than a lot of draw and arcing is that they gap out. Back when they had third rail electric locomotives they were rather long to avoid this. Now they use the P32s, but at GCT they are only allowed in the middle of the upper level, and they idle the diesel until they hit the platform so they can switch back if they need to. If they gap out going outbound, they have to call the RTC to fire the diesel.
As an aside some California pols are pushing for the HSR to use 3rd rail. Any guesses ?.
That's idiotic. In addition to all the other problems, third rail maxes out at 100mph. Pantographs can go to at least 225mph, probably faster.
  by R36 Combine Coach
 
ElectricTraction wrote: Sat Jul 24, 2021 1:49 pm That's idiotic. In addition to all the other problems, third rail maxes out at 100mph.
LIRR has a top speed of 80 and when the Eurostar used third rail, it was restricted to 100 mph in UK.

Any third rail operations over 80 other than the early Eurostar? Original 1968 Budd product literature
on the M-1 described it as a modern high speed car capable of 100 mph, though I'm not even sure any
hit their designed speed.
  by ElectricTraction
 
R36 Combine Coach wrote: Sat Jul 24, 2021 9:12 pm LIRR has a top speed of 80 and when the Eurostar used third rail, it was restricted to 100 mph in UK.

Any third rail operations over 80 other than the early Eurostar? Original 1968 Budd product literature
on the M-1 described it as a modern high speed car capable of 100 mph, though I'm not even sure any
hit their designed speed.
The M-7s can run on 3rd rail at 100mph, but LIRR only maintains their track to 80mph, and Metro-North to 75mph on routes with third rail, so in practice, they only go 80mph at most. In theory, the third track that is coming as part of the $2.6 billion LIRR Main Line Grade Crossing Elimination project should be able to be maintained for a brief run at 100mph, although with all the problems LIRR has, maintaining the equipment or a single piece of track to save maybe a minute shouldn't be on the top of the priority list.

Regardless, the idea of using third rail on high speed rail is idiotic, and the idea of building third rail on any FRA heavy rail project other than expanding electrification on LIRR routes is almost as idiotic.
  by bmvguye39
 
The only reason I mentioned third rail is because I know its used in the NYC area but also because you cant see it so its a less intrusive solution... impractical as it may be.... For the amount of people volume on the north shore, I think full electrification is silly and a waste of money. I think you could run 4-6 car DMUs back and forth to Beverly from Nbpt and Rkpt all day long like shuttle trains and have other trains in Beverly go into the city.... maybe have a few trains run the full route mornings and evenings. My larger point is there are probably decent alternatives than erecting an aluminum cage all the way from Boston to the end points... or come up with a more decent design that doesnt require the poles or posts so closely spaced. Or consider a more euro style cantenary that is less hardware and less cumbersome in design.
  by CRail
 
Some wheels don't need to be reinvented. Sure, it seems foolish to run push pull trains with empty cars, and I don't disagree, but procuring and maintaining two separate fleets for peak and off peak service is far less practical. The only way DMUs make sense is if they were compatible with push-pull equipment and nothing of that sort is FRA approved. These on-board power plant streetcars on steroids that current DMU manufacturers are putting out lack the operational flexibility to make sense for any existing commuter service. They're fine for a start up service trying to establish ridership but that's about it. If we could have DMUs that were just EMUs independent of a power supply my attitude would be different but, for some reason beyond my understanding, we can't.

Just stringing up wire everywhere is outrageously cost prohibitive. I don't see any reason to do so on any north side lines, especially with low hanging fruits like the Dorchester branch, Needham (as it would set up for potential Orange Line conversion), and Stoughton (which has to be done anyways) still waiting to happen. Step number 0 is to bring the Corridor up to capacity to handle our trains and even that isn't happening at this point. Until that happens, even considering north side electrification is nonsensical (my personal opinion; not intended to imply such discussion is unwelcome here).
  by R36 Combine Coach
 
CRail wrote: Sun Jul 25, 2021 10:16 pm The only way DMUs make sense is if they were compatible with push-pull equipment and nothing of that sort is FRA approved.
Some carriers did use RDCs to tow unpowered coaches, but RDCs were not designed or intended for towing and doing so would void Budd's factory warranty.

In those cases, where did the HVAC and lighting on the trailer coaches come from?
  by CRail
 
I'm referring to DMUs being pulled by locomotives and then operating on their own off peak, not them pulling coaches. My idea of the ideal DMU is basically an RDC that would function as a control car AND a self propelled unit. They could be pulled/pushed in a large locomotive hauled consist, and then run as 2 or 3 or 4 car train off peak with no locomotive.
  by eolesen
 
The problem with first generation DMUs was they had a direct drive (geared or hydraulic) vs. traction motors.

The new generation DMUs have traction motors but full width cabs, so just like with light rail, you can't easily add these to another train or consist and have passengers be able to move between cars.

Sent from my SM-G981U using Tapatalk

  by MattW
 
A properly designed full-wdith cab doesn't prohibit that. I know here on Atlanta's MARTA, the cabs are full-width, but with the doors properly configured, there is access between cars (not technically allowed of course). Plus aren't the M7 and M8 cabs full width?
  by R36 Combine Coach
 
M-7, M-8, M-9 have folding cabs and do allow passage between cars, as do the PA5s.
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