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pelhamlocal

Converting system from 3rd rail to catenary, safer idea?

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I know that would be a historical, railfan heartbreaking change, not practical, no money....list goes on, But would it be safer for both passengers during an emergency, track workers, and that god-forbid one with a death wish? An example of successful system wide subway/underground/metro use of overhead power, is the Barcelona metro, though not nearly as old ours, it works. What's your opinion? :)

img_116119.jpg

Edited by pelhamlocal

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Most tunnels and underground stations in the system have low ceilings. But I think it's worth trying on elevated,open-cut and outdoor stations and structures.

Edited by N4 Via Merrick Rd

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Wow, finally some agrees with me, and also i didn't get my head chewed off for post a picture, instead of a link XD

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It would be a lot of work and $$$ to have both 3rd rail and overhead wire system..

 

A good example of your concept at work would be the Metro North New Haven Line, which is 3rd rail here in NYC but once it reaches the Amtrak Northeast Corridor it has to switch over to overhead power, which is why the New Haven electric cars have both 3rd rail shoe and overhead catenary.

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Well, firstly, I'm not sure how many people who find their way onto the tracks are killed or injured by the electricity.

 

I think the more substantial risk to life and limb on subway tracks are the subway trains, and as far as I can see, eliminating trains from the system would pose insurmountable logistical problems.

 

But that aside... I mean if the MTA were hell bent on making the power system safer, I think they'd have a far easier time converting to under-running third rail a-la Metro North than catenary. 

 

I think the clearances within many parts of the subway wouldn't allow enough room for catenary. If you look at Metro North equipment with catenary power, there is a great deal of equipment on top of the car, none of which would fit on a car that needed to enter any of the under-river tubes, for instance. Also, you'll need an insulator between the catenary and the tunnel ceiling, which would further eat into space. 

 

I understand you're posing a hypothetical, but the list of benefits would be small and the list of problems posed is long. Going to have to cast my opinion strongly against on this one. 

 

Although, for what it's worth, the Steinway tunnel that the (7) train uses was originally set up for overhead power - although not from catenary...

steinwaysmall06a.jpg

 

The tunnels were originally built for streetcars, which used an overhead third rail. More can be read about half way down the page here

 

http://www.nycsubway.org/wiki/The_Steinway_Tunnels_(1960)

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Soon enough you'll have technology to have 100% safe inductive power transmission via a central panel. For looks, Think Bombardier Innovia Metro, but traditional axle-motor set-up instead of linear induction motor and panel running down the center is for short-range high frequency wireless power transmission with no third rail. That would be ideal for subways, especially ours. Alas, between development time and costs, never happening in NYC, even if the tech magically becomes 100% ready tomorrow.

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Soon enough you'll have technology to have 100% safe inductive power transmission via a central panel. For looks, Think Bombardier Innovia Metro, but traditional axle-motor set-up instead of linear induction motor and panel running down the center is for short-range high frequency wireless power transmission with no third rail. That would be ideal for subways, especially ours. Alas, between development time and costs, never happening in NYC, even if the tech magically becomes 100% ready tomorrow.

 

A subway draws 6000 Amps at 625 Volts when starting. If you're counting, that's 3.75 Megawatts. I don't think they've sent so much as a kilowatt via inductive coupling. Inductive coupling also generates significant waste heat.

 

I really don't think you're going to send Megawatt power over induction - they've discussed using microwave transmitters paired with rectifying antennas for this level of power transmission - but, if you want to ride a subway on top of a 3 Megawatt microwave transmitter, be my guest: I'll take the bus. Don't forget your tinfoil trousers!

 

I'm not even going to get into the idea that what if some jackass is wearing a necklace that's the resonant frequency of the inductor?

 

Anyway to reiterate my point - I think trains are responsible for far more subway track deaths than the third rail. I think replacing it is a solution in want of a problem. 

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Overhead had a higher mantince cost. You have to maintain the support structures and keep the wire taugt at all times. When you're going 150 to 200 MPH, the wire is always best given the current level of technolgy (I do maintain wire will be phased out within 100 years, and get mocked for it, but so be it)

 

But subway trains, it's a miracle they can even get to 60, and that's out of nesseity in the 60th street tube.

 

think about it for 2 seconds. If the subway were to convert to overhead, that would mean hundrids of miles of wire to be strung. I don't know of anyone who's gone on a whole hearted change of their power supplies in the recent years. Sure there are lines that are electirfying, but I don't hear people talking about ripping out one method for the other.

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A subway draws 6000 Amps at 625 Volts when starting. If you're counting, that's 3.75 Megawatts. I don't think they've sent so much as a kilowatt via inductive coupling. Inductive coupling also generates significant waste heat.

 

I really don't think you're going to send Megawatt power over induction - they've discussed using microwave transmitters paired with rectifying antennas for this level of power transmission - but, if you want to ride a subway on top of a 3 Megawatt microwave transmitter, be my guest: I'll take the bus. Don't forget your tinfoil trousers!

 

I'm not even going to get into the idea that what if some jackass is wearing a necklace that's the resonant frequency of the inductor?

 

Anyway to reiterate my point - I think trains are responsible for far more subway track deaths than the third rail. I think replacing it is a solution in want of a problem. 

It won't be easy, but they will get there eventually. MIT is working on systems to make this more viable, as is Qualcomm in the private sector.

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Another issue...the ceiling clearance is low, and the electricity from the wires, touching the car body, can be very not good.

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I really don't think you're going to send Megawatt power over induction - they've discussed using microwave transmitters paired with rectifying antennas for this level of power transmission - but, if you want to ride a subway on top of a 3 Megawatt microwave transmitter, be my guest: I'll take the bus. Don't forget your tinfoil trousers!

It'll have the doubly beneficial side effect of forcing the MTA to install protective platform barriers and it'll dose any vandals that sneak in with a bit of well-deserved radiation.

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It'll have the doubly beneficial side effect of forcing the MTA to install protective platform barriers and it'll dose any vandals that sneak in with a bit of well-deserved radiation.

Said power distribution system could be "on" only a short distance in front of and behind the train if integrated with CBTC. Since the individual coils transmitting power would be tuned for only a tiny range of frequencies to match receiving on the train, the "radiation" concern becomes moot. Otherwise, the line-up of coils transmitting would be off when no trains are present but turn on/off based on CBTC-supplied train location data. In a sense, a "moving block" but in terms of power transmission and not signal data. Could work. Like I said, Qualcomm is already working on a version of this for roads, Bombardier has the super basic principles for their Primove technology, and MIT is researching the crap out of wireless power transmission (including the resonant frequency stuff). Reason I bring up this decade-away-at-least stuff is because if we're talking changing power delivery for the subway, this technology would be better as it could actually fit in the tunnels and get rid of a live third rail.

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Said power distribution system could be "on" only a short distance in front of and behind the train if integrated with CBTC. Since the individual coils transmitting power would be tuned for only a tiny range of frequencies to match receiving on the train, the "radiation" concern becomes moot. Otherwise, the line-up of coils transmitting would be off when no trains are present but turn on/off based on CBTC-supplied train location data. In a sense, a "moving block" but in terms of power transmission and not signal data. Could work. Like I said, Qualcomm is already working on a version of this for roads, Bombardier has the super basic principles for their Primove technology, and MIT is researching the crap out of wireless power transmission (including the resonant frequency stuff). Reason I bring up this decade-away-at-least stuff is because if we're talking changing power delivery for the subway, this technology would be better as it could actually fit in the tunnels and get rid of a live third rail.

 

Theoretically then, if you're integrating the power distribution with the signaling system, wouldn't it be easier to segmentize the third rail far more than it currently is, and only turn it on when there's a train in the block?

 

I don't mean to constantly oppose your point - I think wireless power transmission is fascinating and valuable, and apparently Bombardier Primove is already transmitting power wirelessly by inductive coupling at the 200kW level, which is much higher than I thought possible.

 

All I'm saying is that inductive power distribution makes sense for the markets that Bombardier is targeting: Buses, Streetcars, and Electric Vehicles. These are running at grade, and on streets, where live electrics would pose large dangers. Down in the tunnels, the tracks are grade separated - nobody should be near that third rail anyway. So what problem are we solving by replacing a functional power distribution system with something new? As I said I don't think a large number of people have been injured by the third rail - but if it's a priority to make it safer, you might borrow an idea from the inductive principle and only energize the third rail where needed after segmentizing it further than it is now. Hell, make it under-running while you're at it. 

 

(although I don't know how you're going to do that without shutting down the entire system for a few years)

 

I will concede that yes, at least the inductive system could fit in the tunnels, so it's a better idea than catenary - but I still maintain we're trying to solve a problem that doesn't really exist. Primove might be an interesting candidate for SBS though...

 

OH, also, have you looked between the subway tracks lately? Lets talk about water intrusion... That's not a place I'd install sensitive electronics if I could avoid it. 

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Its not a bad idea but then considering there would have to be 800+ miles of cables set up everywhere and with low ceilings in the tunnels and crazy people who think theyre badass and then they jump and touch one, yeah, it really would not be the best idea, so I think third rail is just fine, we worked with it for 100 years we can go on perfectly with it

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Theoretically then, if you're integrating the power distribution with the signaling system, wouldn't it be easier to segmentize the third rail far more than it currently is, and only turn it on when there's a train in the block?

 

I don't mean to constantly oppose your point - I think wireless power transmission is fascinating and valuable, and apparently Bombardier Primove is already transmitting power wirelessly by inductive coupling at the 200kW level, which is much higher than I thought possible.

 

All I'm saying is that inductive power distribution makes sense for the markets that Bombardier is targeting: Buses, Streetcars, and Electric Vehicles. These are running at grade, and on streets, where live electrics would pose large dangers. Down in the tunnels, the tracks are grade separated - nobody should be near that third rail anyway. So what problem are we solving by replacing a functional power distribution system with something new? As I said I don't think a large number of people have been injured by the third rail - but if it's a priority to make it safer, you might borrow an idea from the inductive principle and only energize the third rail where needed after segmentizing it further than it is now. Hell, make it under-running while you're at it. 

 

(although I don't know how you're going to do that without shutting down the entire system for a few years)

 

I will concede that yes, at least the inductive system could fit in the tunnels, so it's a better idea than catenary - but I still maintain we're trying to solve a problem that doesn't really exist. Primove might be an interesting candidate for SBS though...

 

OH, also, have you looked between the subway tracks lately? Lets talk about water intrusion... That's not a place I'd install sensitive electronics if I could avoid it. 

You make good points. The reason I prefer contact-less power transmission is that you're no longer sensitive to heavy snow or flooding ruining things. The actual coils would be placed (like AirTrain's tracks for a reference of how it could look, only with no third rail) in a water-tight panel running down the center. At that point, it is safer from flooding and worst case it suffers no more than third rail. Segmenting the third rail to sync up with train location would be a bit of a pain with constant breaks and the added noise of the shoe clipping at the breaks (bloody annoying sound it is at underground stations with a break on the express track in the station). The other benefit of wireless power is no friction. No friction means no shoes to replace. No shoe sticking out to strike debris on the tracks is another benefit. The last thing is, of course, not having any sort of live power (and even when powered not affecting those on the tracks) risking track workers doing routine inspection or people falling on the tracks. All that being said, it'll take a while for such a thing to come to exist. The underlying technologies are there, but it'll take a business case for companies to investigate, develop and market such a subway power delivery system.

 

As for how to install it? Good question. It would probably be best for smaller systems that shut down overnight and for new ones. I doubt we'd see anything like that in NYC for a century even if the product magically became available tomorrow.

Edited by Culver

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