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File: 1615329266586.jpg–(115.08KB, 800x573, Arcing_pickup_shoe.jpg)
lets talk about the types of electrification
third rail, overhead lines, voltage variation, DC/AC etc.
¨ No.3416
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Glorious juice jacks
¨ No.3440
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It just works, OK?
¨ No.3443
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It's funny that multiple such maps attribute Russia to the 3 kV DC club when in general we are electrified with 25 kV AC, although European part is mostly on the DC system, since the electrification here is older. Yet this map even went into the effort of highlighting the different regions of other countries with distinct electrification system, or lack thereof, still it assumes Russia being DC only :/
¨ No.3448
Ireland's electrification only extends as far as the Dublin Area Rapid Transit.
Meanwhile, 25Kv is slowly spreading towards Bristol and Cardiff, so that black area in South-West England and South Wales is about to turn red.
¨ No.3449
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Scotland has been rolling out electrification across the central belt over the past 10 years. Whifflet to Glasgow Central via Mount Vernon was in 2014.
¨ No.3450
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Here we see one of the first electric trains to call at Mount Vernon.
¨ No.3451
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The Paisley Canal branch was electrified in 2012. The low budget electrification involved lowering track under some bridges to provide clearance for the wires. This has unfortunately restricted the loading gauge on the line and I heard that certain freight trains are now barred from the route, resulting in the closure of Hawkhead oil siding.
¨ No.3452
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314212 at Paisley canal station.
¨ No.3453
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By far the most ambitious electrification scheme has been the "Edinburgh-Glasgow Improvement programme". This involved electrifying the routes from Glasgow Queen Street to Edinburgh via Falkirk and to Dunbland via Stirling. Major remodelling of Queen Street Station was carried out in conjunction with the project.
¨ No.3484
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Meanwhile in greece where only the main line is electrified and soon getting a high speed line using italian frecciargento trains
¨ No.3543
Pathetic American locomotives running off 120 AC.
¨ No.3583
There is actually a railroad in Iowa that runs on 600v AC https://en.wikipedia.org/wiki/Iowa_Traction_Railway
¨ No.3584
Why would they run AC?
¨ No.3591
why would they run DC? it's a pain in the ass to make and it does bad things to current collection gear compared to AC.
¨ No.3592
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DC is easey to make (pic related) and you don't have to deal with losses due to the skin effect.
¨ No.3594
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You guys what? It's pretty much general knowledge that AC is a more efficient system for mainline railways, what are you even arguing about?

AC allows one key feature: much higher voltage (via the fact you can easily convert it to usable voltage via the transformer in the locomotive) which allows for less current and thus much longer power supply sections, with less substations. That's why for the past 60 years ALL newly electrified railways are electrified on AC, unless otherwise is done for compatibility reasons. For modern traction drives it's pretty much irrelevant, in terms of efficiency, would you feed it with AC or DC.

If AC would be inferior, WHY WOULD IT BE THE PRIMARY CHOICE FOR NEW ELECTRIC LINES?.. Ah screw it, whenever I try to disprove someone here, no one listens to me anyway.

120 what? 120 Volts? What are we talking here, a garden railway?
¨ No.3597
Are you fuckin serious my dude the first thing modern DC rolling stock does is run DC through an inverter ANYWAY.
¨ No.3598
I suspect it has originally been 600 V DC, but at some point after rectifiers became compact enough to be mounted into locomotives it was changed to AC to eliminate the need to maintain rotary converters or dedicated generators.

Of course, today high power rectifiers have became cheap enough to move them back to the track side, as >>3597 alluded.

The upper one doesn't make sense, I don't see the lone resistor acting even as a resistive voltage divider kind of way, instead it's just parallel with whatever is the assumed load and the voltage they experience would be the RMS voltage but divided by two because it's a half wave rectifier; do I get that right?

The bottom one is the way how all transformer bricks worked before the 2000s. Not a terribly good waveform, but could be filtered with a choke and another parallel capacitor or even yet another choke and a capacitor and that wound suffice even as the main rail of an audio amplifier.

>It's pretty much general knowledge that AC is a more efficient system for mainline railways

Reminding that DC has less transfer losses but stepping the voltage up or down is a bitch. However, power semiconductors are getting yet more cheaper so I wouldn't rule out the possibility of even high power DC-DC converters getting cheaper than conventional AC-AC transformers of a similar power rating. Probably the municipal 115V / 60Hz AC or 230V / 50Hz AC with 11/33kV or 10/20 kV medium voltage systems aren't going to convert to DC in a long while, but the high voltage long distance, high power backbone might just do.
¨ No.3599
No s*** that modern railroad systems are ac they also run into tens of thousands of volts. If you are running 600V already then what is the point of makeing it AC you get less power than if it was 600VDC.
¨ No.3600
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So, while I'm both drunk and stoned (consider the exact time of the post and the time zone), I consider this post internally consistent.

So let's clarify, I assume the locomotives have their original 600 VDC motors fed via rectifier in the locomotive and 600 V AC power-line with the assumption the tolerances of the original 600 VDC insulators would handle the higher peak voltage of the AC.

Would that make sense, and yanks aren't no strangers on huge single phase load's on their medium voltage systems. Just stick a transformers there and they hopefully even out. Our wimpy 20KV/230V 3ph systems are so delicate in comparison :D

>No s*** that modern railroad systems are ac they also run into tens of thousands of volts. If you are running 600V already then what is the point of makeing it AC you get less power than if it was 600VDC

Well no shit my dude, you nailed it with >modern, how ever if you haven't noticed, much of the discussion has been about The Iowa Traction Railway.
¨ No.3601
Putting rectifiers on the locomotive would be stupid. Why transmit that power is a loosey and in inefficient way THEN turn it back to DC when you can just have it be turned to DC at the power station? If they wanted to cut power stations and feeders then tjey would use higher voltage AC and have it steped down and be recitified onbord. 600VAC needs just as maney feeders as 600VDC.
¨ No.3602
Well they may also run their locos with with DC motors in universal motor mode, but to have done that since 1897 when Iowa Traction Company started would be pretty bold. This thing has interurban heritage, which would support originally a DC system.
¨ No.3618
>>3601 – Putting transformers and rectifiers aboard the locomotive or trainset is common, especially since the advent of solid-state power electronics. They are, after all, the least expensive way to feed motors and ETS/HEP from the 15/20/25 kVAC on the OHL.

Aside: There is a list of electric railways in the US on the 'Pedia. It implies that the Iowa line is a 600 VDC line as there is no cycle count supplied.
¨ No.3619
This is correct.

DC is not a great way to do overhead line electrification. 25kv AC is the best way to do OHLE because you do not need as much copper in the actual line, you can space the substations further apart, and AC is more compatible with the commercial grid in most cases. Solid state rectifiers and other ancillary equipment is smaller than it has ever been and still be able to handle the loads of a locomotive, and that is fueling the shift from DC to AC. DC is also subject to voltage drop over long runs, I had the same issue with my HO scale train set where the DC locomotive would try to stall at the point furthest from my power pack. With modern DCC, which is basically AC, power losses are a thing of the past.
¨ No.3625
AC is only good at higher voltages mostelt 10kV pluse anything under 1kV and you should go DC. Also DCC =/= AC but it works better than normal DC because maximum voltage can always be applied no matter the desired speed.
¨ No.3627
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Much of the world runs on 1500/3000 DC.

I agree though, 2x25 kV AC is modernity.

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