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December 17, 2017, 07:43:05 PM *
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Author Topic: Is rail electrification the future, or the past  (Read 2154 times)
Electric train
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The future is 25,000 Volts a.c.


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« Reply #60 on: November 16, 2017, 09:42:34 PM »

This has caused me to recalibrate my understanding (not for the first time on this forum, which is one of the things I like about being here!). I thought that one of the big advantages of pure electric trains was their lighter weight, but if a motor-generator set weighs broadly the same as a step-down transformer then where is the weight saving?

....but the MTU mg set produces 700kW, perhaps 560kW at rail, whereas  the transformer and inverter will produce ten times that, roundly. A 9 car 802 probably has a mass of c400t, so the diesels probably add c10% to that. Power used at higher speeds is more related to turbulence than weight related rolling resistance, so I don't think that the engines will be noticed.

The IEP's will enjoy greater success the more OHLE that they use. Without the wires they will be as under-performing, expensive and  high maintenance as other diesels, needing constant ecs trips to refuelling points.

OTC

About 15MW is the max you could get out of the OLE, at that rate of 600A for to long things will get a bit warm, typically the max power from the OLE is 6MW, even at this level the pathing of trains in electical sections becomes important, you cannot have too many 6MW trains in the same electrical section
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Bmblbzzz
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« Reply #61 on: November 17, 2017, 09:35:48 PM »

Further to hydrogen power...

Couldn't be much further from hydrogen, could it? I mean, it's a gas, but so is Jumpin' Jack Flash...

I love the circular economy though. The older I get, the more I come to think that economics is just a system to add delays and accelerations to the routing of clean and dirty washing.
They mention feeding it into the gas mains, so in terms of combustion products, it's a long way from hydrogen (but still much better than diesel). But unlike CNG or LPG it hasn't been dug out of the ground, it's been made from stuff so surely that makes it in your terms "an energy store" rather than "a fuel". I've no idea how efficient that process is or how it compares to other uses, like fertiliser maybe, but seeing as we produce metric brown bin-fulls of waste food, it's got to be better than putting it in landfill. Of course it might be even better if we didn't throw it away but ate it...
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ellendune
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« Reply #62 on: November 17, 2017, 10:07:27 PM »

They mention feeding it into the gas mains, so in terms of combustion products, it's a long way from hydrogen (but still much better than diesel). But unlike CNG or LPG it hasn't been dug out of the ground, it's been made from stuff so surely that makes it in your terms "an energy store" rather than "a fuel". I've no idea how efficient that process is or how it compares to other uses, like fertiliser maybe, but seeing as we produce metric brown bin-fulls of waste food, it's got to be better than putting it in landfill. Of course it might be even better if we didn't throw it away but ate it...

I have heard of serious proposals to mix hydrogen with methane in the domestic gas distribution network.
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Red Squirrel
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« Reply #63 on: November 18, 2017, 10:04:09 AM »

Of course it might be even better if we didn't throw it away but ate it...

Whisper that when my wife's dog is around - he'd happily eat the contents of our brown bin, throw it up, and then eat it again. An object lesson in recycling, but to my mind somewhat... distasteful.
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Four Track, Now!
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« Reply #64 on: November 22, 2017, 06:32:16 PM »

Whisper that when my wife's dog is around - he'd happily eat the contents of our brown bin, throw it up, and then eat it again. An object lesson in recycling, but to my mind somewhat... distasteful.

Not a new phenomenon - King Solomon had the same canine / brown bin issues some years ago, as well as what sounds like MetroBust.

Quote
As a dog returns to its vomit, so fools repeat their folly. (Proverbs 26:11)
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