AC EMU at M7 weight, then why not the M8?

No Jay my comment was directed at the person that sees only everything wrong by railroad, the Federal Railway Administration, The Association of American Railroads and makes it a all out effort to point it out.
Meanwhile he has no experience in railroading or Railway engineering.

Jay - typical DRN tactic. When he's cornered in an argument, throws insults. No real counter to the argument? Insult. He knows that I'm right - a 150,000 lb per car EMU simply won't work very well (if at all) on third rail.

It's simple physics. You need a lot of HP to move or accelerate. So? well, that translates back to a high amount of motor current. So? Well, the third rail is 650 volts. And that means high current. Which means higher losses through the third rail.

On top of which, the higher electric consumption will push operating costs up. This isn't theory - the LIRR's per passenger mile and per car mile costs have been climbing ever since the heavyweight DE/DM-30s have appeared - from standard reported data, the LIRR's operating expenses per vehicle revenue mile and per passenger mile are the highest they've been in a decade, despite nearly steady ridership levels. There has been a strong upward trend since the late 90s, beginning in 1999, and not seriously leveling off. I suspect the 2004 and 2005 data will show this increase continuing. MN shows the same thing, though somewhat delayed.

NJT's rail segment, which hasn't seen such an equipment change, has held pretty much level. Ditto for SEPTA.

Weight = power, high track forces, and more money. Unless you're in DRN's fantasyland where we can wave a magic wand, go *poof* and make the world perfect.

Phil were do you get your 150 000 Lbs number from, other than your imaginairy thoughts.
Like I said before If you know so much , put your money were your mouth is, send resume To 347 Madison Aveneu and prove your skills.

<i>Phil were do you get your 150 000 Lbs number from, other than your imaginairy thoughts. </i>

It's <b>easy</b>

Take an M-7: 125,000lbs.
Add a pantograph and support gear: +1,000 lbs.
Vaccum breaker and gear: +1,000 lbs
Reinforcing the body to hang a transformer under it: +2,000 - 5,000 lbs.
Moving the braking resistors ontop to make room: +500 - 1,000 lbs
Main tranny: 10,000 - 15,000 lbs
Conversion and changeover gear; 2,000.

Low end? 146,000lbs. We'll be generous and round it to 145,000. 20,000 lb penalty to add AC support? Sounds within the realm of believability.

High end? I hit 150,000 lbs on the button. And I've most certainly lowballed a few numbers here. Add another 5,000lbs or so for 25hz support, a hundred for voltage change ability, and frankly, I tend to think shifting the braking grids to the roof won't be 500 - 1000 lbs. And I suspect the main transformer will weigh more, since I'm quoting something on the order of what a Silverliner has, and the M-8 will need on the order of a metroliner's main tranny. Add a few hundred to a thousand to the conversion gear if you want regeneration to the catenary.

Applying a simple filter: An M-7 weighs 125,000lbs. A main transformer for 1,000HP + HEP will be at least 10,000, and likely on the order of 15,000+. That in itself sets an absolute lower boundry of 135,000 - 140,000 lbs. Since the output of said transformer can't be fed directly into the inverters (or anything else), and we're not even including the primary side - another 5,000 - 10,000lbs of auxilarary gear is very believeable.

I'm sticking with my back-of-the-envelope prediction - you'll see the M-8s, if they're built like the M-2s (i.e. married pairs, every axle powered, transformer per car) but based on the M-7's design- come in around 150,000 lbs, plus minus 5,000.

Guys - this topic is beginning to get a bit heated. Let's just cool down a bit - remember - it's a HOBBY forum.

i got a letter from the mta! it says "we choo-choo-choose you!" and there's a picture of a train!


anyway...what is an HEP,and why do we need it?

second...who made nasadowsk the forum psychotherapist?

third...if everybody hates the m7 then why are we all so stoked about the m8?

Headend(or Hotel) Electric Power is normaly provided by locomotive as power to coaches it powers the Airconditioning , Heat, Lights etc.
On MU's a pair of cars usually has a MA or Inverter for same purpose to power all auxiliaries like Compressor, heat , Airconditioning, lights, battery chargers, etc etc.

Second question I can't answer.

The M7 design are pretty much the base of what any design would look like no matter who would produce it.
The car body style is just about the max for loading profile of railroad.
The propulsion, some kind of AC propulsion would need to be economic and easy maintainable, the weight has to stay within a given max without sacrificing safety or comfort.

certain people no doubt will start their rant about FRA and rules again but the Railroad just will comply as they see need for the same rules.

DRN apparently thinks that Metro-North is exempt from the laws of physics.

But, since he seems to know something everyone else doesn't - let's have HIM explain to us how MN is going to take a 125,000 lb EMU, and add 25,000 lbs of electric gear to it.

Come on dutch - what's the magic that's gonna keep these things from being overweight, poor performing electricity suckers?

Let's hear how they're going to take an already severly overweight EMU, and add a 1.5 Mva transformer, AC/DC converter, pan, body reinforcement, etc, and have something reasonable.

I've given my weight estimates, which are based on actual numbers from actual equipment. And I'll stand by first prediction - 140,000 - 150,000 lbs WILL be the weight of the M-8 cars, if they insist on every axle powered, every car powered.

And at that weight, they will use more electricity and perform worse than the m-2s. They will cost taxpayers more, and deliver far less.

I've given my numbers, Dutch. If you think they're wrong, let's hear <b>your</b> numbers.

With AC propulsin even at higher weight they will never use more power than the M2's.
The M2's basicly have two propulsion groups one DC Cam controller and a AC propulsion system both of whom use grid resistors to step down current for the motors.
A AC propulsion only needs a small brake grid incase the catenary is not receptive to regeneration.
The M7 design is dead, a total new M8 design is being worked on.

<i>With AC propulsin even at higher weight they will never use more power than the M2's.</i>

If they've got the same HP as the M-2s. AC ain't magic, and it's not 100% efficient - 95% if you don't mind noise, skip bands, and other fun issues. Outside of starting up (i.e. high resistance in the circuit on a DC system), it's not much better than DC in a number of cases. And the M-8s won't be able to really regen in DC mode (i.e., third rail power) This isn't a technical issue, it's just the reality that the chances of 2 trains being on the same circuit isn't very high, and the substations can't accept the power and do anything useful with it. Regen on AC power? Sure. But don't expect a miracle - I believe 30% is about the insustry average

As far as braking grids - they're needed more because the cars have to run on third rail - the ALP-46s don't have grids at all and do well without them (though they can't regen as much in push as they can in pull because of a few technical issues. I should point out that a few EEs at NJT despise the things because of the lack of grids

More to the point - the HP of the car is still a very good predictor of electrical draw, regardless of system. The only way to keep the electric draw the same is to keep the HP the same (within the +- 10% or so variation between different types of control systems)

Even the Alp-46 has a braking grid , its just not on the roof.
The Dynamic brake has to keep working 100% even when going over a bridge , phasegap, or ripped off or dropped pantograph.

No dutch, it has no grids. I heard this right from a guy at NJT's engineering department, while discussing stuff on substation project for them. It's been a <b>big</b> sticking point among the various people there (for lots of reasons not related to braking, actually), but they don't have them. I know, weird as hell, but they don't. It's regen or friction braking. No room inside the thing for braking grids, and grids that size have to be roof mounted anyway because of the heat considerations (6+ MW). There's a tiny grid up on the roof, I'm not sure what that's for, but I was told it's not braking.

FRA demands that all braking functions work regardless of conditions.
So a train that starts braking with blended brake (dynamic) needs to keep that funtion at all times regardles what your NJT buddy says.
If its regeneratibe to HEP it also needs to work if HEP fails
If its Regenerative to power source it needs to work even if no source is present.
the failsafe grid on the M7 is very small too.

There's been quite a bit in the papers recently about the M2s age, and it appears that things are starting to move.

The question is, what is a realistic timeline for "M8"s being in-service - assuming out beloved CDOT gets $700+ MM in funding? I keep hearing 2008, and my sense is that is NOT realistic. Are we really looking at 2010 or 2011?

Why doesn't Sumitomo bid on these cars? They have extensive DC experiance out here in Chicago. Because they farm out most of the electricals to GE, the transition to AC can't be that hard.

I don't remember how the M-series cars ride, it's been 7 years since I rode LIRR and I've never been on MNCR.