(Tech) Single EMU design for all NYC-area lines?

[amm in ny]

As a result of discussions about running Metro-North EMUs into (NYC) Penn Station, I got to thinking:

1. How technically feasable would it be to build a single EMU design that could be used (without modification) on all the NYC-area electric lines? That is:

* AMTRAK (NEC)
* Metro-North -- New Haven, Harlem, Hudson lines.
* LIRR
* NJ Transit

The design would have to fit all clearances, handle overhead wire, over- and under-running 3rd rail, and all voltages and frequences. It would also need to handle the various PTC systems in use or being installed. (Bonus points if it works on SEPTA as well.)

Would it simply involve bolting existing solutions onto a basic (more or less existing) carbody design? Or would development work be involved?


2. If it were feasable, are there any WAGs as to how much more expensive this would be than the current system, where each agency orders its own equipment, more or less independent of the others.

NOTE: I'm not asking whether people here would consider it a good idea to build and buy such a design, or whether the agencies would ever even consider it. That's a separate question, and I'd rather not get into it in this thread, since I suspect it (and the politics involved) would forstall discussion of the technical aspects.

NOTE TO MODS: I put this in the "General Discussion" forum since it didn't seem to apply to any one of the systems involved. Please move it if you think it belongs elsewhere.

[DutchRailnut]

Is it possible, not really
Amtrak, needs high speed equipment, not something geared for Commuters.
Metro North, why run a M-8 type car on Harlem or Hudson, big weight penalty for AC/DC setup.
LIRR, does not have clearances to have roof top mounted equipment in ESA and some other locations.
NJT, needs equipment that is low level accessible, and why would they drag DC equipment around ?

[Adirondacker]

As a result of discussions about running Metro-North EMUs into (NYC) Penn Station, I got to thinking:

1. How technically feasable would it be to build a single EMU design that could be used (without modification) on all the NYC-area electric lines? That is:

* AMTRAK (NEC)
* Metro-North -- New Haven, Harlem, Hudson lines.
* LIRR
* NJ Transit

It's technically possible. Things that can go fast accelrately slowly and things that can acclerate fast can't get up to high speeds. Going fast is important when the stations are tens of miles apart. Acclerating fast is important when the stations are a mile or two apart. A car that makes compromises would make Amtrak, the commuter railroad or both slower. So Amtrak is in a separate class.

The commuter railroads all want something that accelrates fast and don't need high speeds. ..... using MARC or NJTransit equipment for the holiday extras Amtrak runs between NY and DC adds a half hour to the trip versus using Amfleets....

If it was cheaper to do, Metro North wouldn't have any M7s, they'd be running all M8s. They don't. Running M8s on Long Island would make even less sense. They don't run over any electrified track that is without third rail. Same thing with NJTransit but they have catenary over all the electrified rail they use. There isn't any third rail anyplace else either. Probably won't be.
... when Salt Lake City decides to electrify they can just order up some of what NJtransit ordered last. Like MARC and AMT do. Or what SEPTA ordered last but for 60Hz and 25kV.

[mtuandrew]

NOTE TO MODS: I put this in the "General Discussion" forum since it didn't seem to apply to any one of the systems involved. Please move it if you think it belongs elsewhere.

Thanks, amm. Since your question depends on the limitations of the different railroad systems around NYC, we can leave it here for a while.

As for the question, it sounds like this design would:
-have a single level, with room for overhead luggage racks
-be powered from 11/12.5/25 kVAC 60 Hz/25 Hz overhead and 750 VDC under- and over-running third rail
-be capable of 125 mph
-be light enough for low-capacity LIRR branches
-have a high capacity configuration
-have at least one set of bathrooms per car
-have a full-width engineer cab and a front door that meets Amtrak certification, as well as allowing for mid-train use
-be equipped for full ACSES and cab signals
-have both high-level quarter-point doors and trap-equipped end doors
-fit within an ESA-sized loading gauge.

On the plus side, if it worked on both the Metro-North and New Jersey Transit systems, it would automatically work on SEPTA too. Regardless though, it's a tall order, primarily because it would need both 25 Hz and DC capability in the same car without being overly heavy or large.

By that point though, one might as well design a single car shell that can be fitted with either AC or DC equipment (see the M-1 and M-2), but that could control both types of cars. If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

[amm in ny]

It's technically possible. Things that can go fast accelrately slowly and things that can acclerate fast can't get up to high speeds. Going fast is important when the stations are tens of miles apart. Acclerating fast is important when the stations are a mile or two apart..

Interesting. I wonder why that is?

Electric motors are famous for having fantastic torque at low speeds, and the same horsepower that can deal with the drag at 125 mph ought to be able to do fast acceleration. What technical factors am I showing my ignorance of?

[amm in ny]

-be capable of 125 mph

AMTRAK requirement, I assume.

-have at least one set of bathrooms per car

Is this an AMTRAK requirement? Metro-North doesn't have this, just one bathroom per pair.

it's a tall order, primarily because it would need both 25 Hz and DC capability in the same car without being overly heavy or large.

Metro-North did this in the days when the NH line was 25 Hz. And I assume that they had cars that could handle either 25Hz and 60Hz (and DC), to handle the switch from 25Hz power to 60 Hz power.

If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

Why would you have unpowered cars? Doesn't the 11-25 KV 60Hz (or 25 Hz) get converted to "low" voltage (=several hundred volts) DC, anyway?

[mtuandrew]

-be capable of 125 mph

AMTRAK requirement, I assume.

Yep, referring to Amtrak - they seem to have no interest in new sub-125 mph equipment.

-have at least one set of bathrooms per car

Is this an AMTRAK requirement? Metro-North doesn't have this, just one bathroom per pair.

I have never seen an Amtrak coach without bathrooms, and assume it is a requirement.

it's a tall order, primarily because it would need both 25 Hz and DC capability in the same car without being overly heavy or large.

Metro-North did this in the days when the NH line was 25 Hz. And I assume that they had cars that could handle either 25Hz and 60Hz (and DC), to handle the switch from 25Hz power to 60 Hz power.

From some research on the M-2/4/6 series, they appear to have been delivered with 11/12 kVAC 25 Hz capability as well as 660/750 VDC, but they obviously operate on 60 Hz AC today. Can one of the Metro-North contributors let us know how easy it was to convert a Cosmopolitan Car from 25 Hz to 60 Hz? The Arrow cars on NJT are also manually convertible, though they don't have third rail - maybe an NJ Transit person can let us know a bit about that process too.

Perhaps a tri-voltage car isn't as difficult as I thought.

If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

Why would you have unpowered cars? Doesn't the 11-25 KV 60Hz (or 25 Hz) get converted to "low" voltage (=several hundred volts) DC, anyway?

True, but the FRA prohibits bussing traction power from one car to another. You might be able to get away with a permanently-married pair, one with the 25 Hz equipment and the other with the 60 Hz, with third-rail shoes mounted on all trucks, but I'm not the one to ask.

[amm in ny]

If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

Why would you have unpowered cars? Doesn't the 11-25 KV 60Hz (or 25 Hz) get converted to "low" voltage (=several hundred volts) DC, anyway?

True, but the FRA prohibits bussing traction power from one car to another. You might be able to get away with a permanently-married pair, one with the 25 Hz equipment and the other with the 60 Hz, with third-rail shoes mounted on all trucks, but I'm not the one to ask.

Metro-North NH line EMUs have one pantograph per pair (or triple), so I assume that traction power is distributed from one car to another. AFAIK, there are shoes on all trucks (I can take a look the next time I have a few minutes to spare at GCT.)

AFAIK, MNCR EMU pairs can only be separated at the shop, and I assume the power linkage is via well-insulated cable. (Remember the buffer-like contactors over the end doors on some cars 50+ years ago?)

After all, they wouldn't want to have exposed objects energized with > 750 volts to ground out in the open where just anyone could come in contact with them.

And married pairs provide obvious savings; is there much of a down side to them, assuming the equipment is reliable?

[MattW]

If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

Why would you have unpowered cars? Doesn't the 11-25 KV 60Hz (or 25 Hz) get converted to "low" voltage (=several hundred volts) DC, anyway?

True, but the FRA prohibits bussing traction power from one car to another. You might be able to get away with a permanently-married pair, one with the 25 Hz equipment and the other with the 60 Hz, with third-rail shoes mounted on all trucks, but I'm not the one to ask.

Do you know where it's codified that you can't run traction power between cars? I've scanned the FRA's section in the CFR and the U.S. Code, but see nothing that outright prohibits this.

[kaitoku]

By that point though, one might as well design a single car shell that can be fitted with either AC or DC equipment (see the M-1 and M-2), but that could control both types of cars.

This is doable, and the modular designs of some railcar builders are made just for these applications (Hitachi's A-train, and perhaps Siemens Desiro, among others). But this veers into the questionable situation of depending on a single manufacturer for all stock in a huge metropolitan area, when having at least two would seem prudent.

[mtuandrew]

Do you know where it's codified that you can't run traction power between cars? I've scanned the FRA's section in the CFR and the U.S. Code, but see nothing that outright prohibits this.

I don't, sorry. I have seen it on a government site, but I can't say where. Again though, that apparently only counts for cars that are conventionally coupled together.

[Adirondacker]

Interesting. I wonder why that is?

Dutch was saying the same thing when he said "not something geared for Commuters".

Electric motors have limits. If it's geared for high speeds it won't accelerate fast and if it's geared to accelerate fast it won't go to high speeds. The odd peculiar things they are doing with inverters and variable speed motors broadens that somewhat but things that accelerate fast can't go fast and things that can go fast don't accelrate fast.

You want them to have trains that accelerate fast if you are commuter. A train is optimized for 100 and a top speed of 125. It then accelerates as fast as it can. If the next station is a mile or two away, it gets to 90 before it has to start slowing down. ( If it can. most commuter lines aren't maintained for 100 or even 90. If they were there are curves. ) The commuter train with a top speed of 100 can get to 70 quickly, stay there for a while and since it's only going 70, stop in a much shorter time. It gets to the next station faster. Not by much but add that up over ten stations and the trip is shorter. By a few minutes. that's important when you are running commuter trains. After a whole day you squeeze another trip out of the train. And the commuters got a faster trip. curves.. if you are on a commuter line with curves you want something that can accelerate fast.

It gets worse when the train is able to go 150 or 200.

[amtrakowitz]

NOTE TO MODS: I put this in the "General Discussion" forum since it didn't seem to apply to any one of the systems involved. Please move it if you think it belongs elsewhere.

Thanks, amm. Since your question depends on the limitations of the different railroad systems around NYC, we can leave it here for a while.

As for the question, it sounds like this design would:

• have a single level, with room for overhead luggage racks
• be powered from 11/12.5/25 kVAC 60 Hz/25 Hz overhead and 750 VDC under- and over-running third rail
• be capable of 125 mph
• be light enough for low-capacity LIRR branches
• have a high capacity configuration
• have at least one set of bathrooms per car
• have a full-width engineer cab and a front door that meets Amtrak certification, as well as allowing for mid-train use
• be equipped for full ACSES and cab signals
• have both high-level quarter-point doors and trap-equipped end doors
• fit within an ESA-sized loading gauge.

On the plus side, if it worked on both the Metro-North and New Jersey Transit systems, it would automatically work on SEPTA too. Regardless though, it's a tall order, primarily because it would need both 25 Hz and DC capability in the same car without being overly heavy or large.

By that point though, one might as well design a single car shell that can be fitted with either AC or DC equipment (see the M-1 and M-2), but that could control both types of cars. If an agency wanted to run from 60 Hz to third rail to 25 Hz, they could use multiple types in the same train and deal with the weight penalty of dragging unpowered cars.

Having both high-only quarter-point doors and end doors with traps would take up too much revenue space. SEPTA's Silverliner V has quarter-point high/low platform doors with trapdoors and "long doors". There were indications that before the Rotem design won the SEPTA bid, a modified version of the Bombardier M7 (or even Kawasaki M8) could have been built with steps, trapdoors and "long doors" also

Nothing with a pantograph (even locked down) is going to fit in the ESA's loading gauge, AFAICS. If that were possible, then LIRR's C3s and DM30ACs could use ESA, which, I am led to understand, they can not; EMUs with roof height of 12' 8" having a pantograph locked down will have a total overall height of at least 14' 6", the same as the roof height the C3 and DM30AC; and EMUs that possess dual DC third rail/high-voltage AC overhead equipment often have their extra electrical equipment installed on the roof, making the roof height much greater than 12' 8" (since the Cosmopolitans).

I also do not see how or where Amtrak is requiring that any new commuter EMU has to be capable of 125 mph MAS, nor even have a full-width cab. SEPTA's Silverliner V has a half-width cab and an apparent MAS of 110 mph; these entered service only three years ago. 125 mph is not going to affect the average speed of commuter trains versus a higher rate of acceleration.

[Adirondacker]

I also do not see how or where Amtrak is requiring that any new commuter EMU has to be capable of 125 mph MAS, nor even have a full-width cab. ...125 mph is not going to affect the average speed of commuter trains versus a higher rate of acceleration.

If you want to run the express to Long Branch or Trenton on the express tracks it has to if the Amtrak trains are coming through at 160. They aren't doing all of this work so that one Acela an hour can come through. They are doing all this work so there will be two Acela IIs coming through an hour and the Regionals are using the old Acela equipment until the second batch of Acela IIs arrive when there will be two Regionals an hour.

[mtuandrew]

I also do not see how or where Amtrak is requiring that any new commuter EMU has to be capable of 125 mph MAS, nor even have a full-width cab. ...125 mph is not going to affect the average speed of commuter trains versus a higher rate of acceleration.

If you want to run the express to Long Branch or Trenton on the express tracks it has to if the Amtrak trains are coming through at 160. They aren't doing all of this work so that one Acela an hour can come through. They are doing all this work so there will be two Acela IIs coming through an hour and the Regionals are using the old Acela equipment until the second batch of Acela IIs arrive when there will be two Regionals an hour.

In addition, the original poster posited that Amtrak would also use such equipment. They have shown a clear preference for 125 mph operation, and seem to prefer a full-width cab judging from the work done on their former Metroliner cab cars. If they weren't interested, a 100 or 110 mph top speed would probably suffice for most operators.