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How electric trains work and why they make interesting sounds [video]

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Re: How electric trains work and why they make interesting sounds [video]

#21

Post by itishappy »

theideaofcoffee wrote: post #13

As much as I love the futuristic and sophisticated sounds that electric traction drives make as compared to their fossil-fueled counterparts, I do think that the driving and control systems that actually generate the PWM waveforms that are sent to the motors are even more interesting. Huge, massive IGBTs weighing a kilo+ each chopping up hundreds of thousands of joules/s of energy without destroying themselves, curre…

Same! That stuff is so freakin' interesting! The other deep dive I really want (pun intended) is submarine sonar transducer drivers, which as I understand do basically the same thing but bidirectional and with a LOT more waveform customization.

Re: How electric trains work and why they make interesting sounds [video]

#22

Post by euroderf »

stackghost wrote: post #19
jimmaswell wrote: post #18

I still find it amusing that most fossil fuel trains only burn it to power a generator, with the wheels run by electric motors. It makes perfect sense with the massive startup torque a train requires, something electric motors are much better at.

The term for that is a hybrid series powertrain. It allows one to optimize the generator to run at a single RPM, which leads to efficiency benefits.

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

Re: How electric trains work and why they make interesting sounds [video]

#23

Post by Loughla »

euroderf wrote: post #22
stackghost wrote: post #19

Earlier quoted context omitted.

The term for that is a hybrid series powertrain. It allows one to optimize the generator to run at a single RPM, which leads to efficiency benefits.

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

Re: How electric trains work and why they make interesting sounds [video]

#24

Post by gambiting »

Loughla wrote: post #23
euroderf wrote: post #22

Earlier quoted context omitted.

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

I have a PHEV and I genuienly believe this is the best combination of both, it's so practical with upsides of both drivetrains, but also let's not kid ourselves - PHEVs are vastly more complicated than either just plain ICE or EV cars, you have a lot more stuff that can go wrong. I deal with it by just buying extended warranty for as long as they let me lol, but it's definitely a concern with them.

Re: How electric trains work and why they make interesting sounds [video]

#25

Post by rootusrootus »

Loughla wrote: post #23
euroderf wrote: post #22

Earlier quoted context omitted.

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

What would you say the bad part is for a BEV?

Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.

Re: How electric trains work and why they make interesting sounds [video]

#26

Post by rootusrootus »

mlok wrote: post #4

It's a mystery to me how the camera is mounted for the video at 7:55. https://youtu.be/IRJIJPTUXXE?t=474 A drone ? The camera follows the train so precisely that it seems it is mounted on the train, but it passes on the other side of some objects so it cannot be mounted on it.

Simulations have gotten quite good, apparently. It threw me for a loop for a moment, too, until I figured out what was going on.

Re: How electric trains work and why they make interesting sounds [video]

#27

Post by rwmj »

theideaofcoffee wrote: post #13

As much as I love the futuristic and sophisticated sounds that electric traction drives make as compared to their fossil-fueled counterparts, I do think that the driving and control systems that actually generate the PWM waveforms that are sent to the motors are even more interesting. Huge, massive IGBTs weighing a kilo+ each chopping up hundreds of thousands of joules/s of energy without destroying themselves, curre…

Photo on Wikipedia:

https://en.wikipedia.org/wiki/Insulated-gate_bipolar_transis...

Are they manufactured using regular silicon lithography? You'd think when making something so large you could just mix up the chemicals instead.

Re: How electric trains work and why they make interesting sounds [video]

#28

Post by rootusrootus »

Great video, lots of nice details. Now I wonder what technology our local light rail train is using, because I've noticed the gear switch sound (though it just has a single switch at perhaps 10-15 mph or so). Apparently it's a Siemens S70 (there are several varieties of rolling stock, but this is the one that makes the most distinctive sounds).

Re: How electric trains work and why they make interesting sounds [video]

#29

Post by rsynnott »

stackghost wrote: post #19
jimmaswell wrote: post #18

I still find it amusing that most fossil fuel trains only burn it to power a generator, with the wheels run by electric motors. It makes perfect sense with the massive startup torque a train requires, something electric motors are much better at.

The term for that is a hybrid series powertrain. It allows one to optimize the generator to run at a single RPM, which leads to efficiency benefits.

Some buses also use these. Dublin Bus has a particularly disconcerting plugin hybrid variety; if it’s using the diesel engine, that runs constantly (so it’s noisier than a normal bus at rest) but if on battery, it’s silent. There are few things more unnerving than a double decker bus gliding along virtually noiselessly (their pure-electric buses, somehow, are noisier). Double-decker buses are supposed to sound like they might explode at any moment, like in the good old days.

(/s, just in case; ye olde 20 tonne 1980s buses were extremely noisy, and it was not great.)

Re: How electric trains work and why they make interesting sounds [video]

#30

Post by asciii »

jkingsman wrote: post #10

Fascinating video! One of my favorite train vids is a Taurus starting up in frigid conditions. As the wheels slip and the PWM modulation on the individual motors varies to keep traction, it makes beautiful music. https://www.youtube.com/watch?v=Q_bF1Wb_pSE

That's really neat - it sounds like a violin. I can barely keep a tune so I'm wondering if anyone knows anything special about the melody
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