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.
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
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, current transformers, contactors, it really tickles parts of my brain. He only spent a handful of seconds on those, would be interesting to hear a deeper dive.
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.
From what I understand, mostly yes. They are still built up layer-by-layer with standard litho techniques, with pattern masks, ion implantation for the p- and n-type layers, etching, CVD to deposit insulation material (for the 'insulated gate' part of the device). Though they don't have to be nearly as precise, as I understand it as something more sophisticated, like a cpu, they still need to lean on those to make it chooch.
I don't thik they're produced with the same process as CMOS, but I bet some photolithography is involved.
Very early EVs (GM's EV1 and then a few other GMs) used banks and banks of water cooled IGBTs to spin the motor.
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.
I do not have perfect pitch (cool party trick), but I can identify all 8 'normal' equal temperament intervals by ear relative to a reference (If you couldn't guess, I play bass, which is a lame party trick).
I was in Austria last year, and a bunch of the trains starting from a standstill had a "gradual acceleration" algorithm for their traction motors. As the drive frequency increased, you could hear the drive motor whine (or maybe it was the inverter?) along with the frequency. It was fascinating, because it played chords as it accelerated: root, 2nd minor, 4th major, 6th minor, octave, then it would pause at the octave and do it again after a few seconds until it reached max power I assume. Each chord had a very faint tritone added to it relative to the chord tonic, so you got this really harmonic pulsing.
After the second course there was too much rail noise to hear what happened, but it was fascinating. I'll try to find a video, I know I recorded it.
Power in Austria/Germany is delivered to trains via a really weird standard too: something like 25hz 27 kV. Leftover standard from 100 years ago.
25kv 50/60Hz is the norm.
The German standard you are thinking of is 15kv 16.7Hz.
Normally it just plays the scale: https://www.youtube.com/watch?v=-SDYdHzT7Qw
But it can be configured to play other tunes. Here is a rare recording of it playing the Austrian anthem: https://www.youtube.com/watch?v=UkdQmDGU9AM (another recording: https://www.facebook.com/unsereOEBB/videos/290883783832057/)
Some OBB locomotives have their PWM systems tuned so that when they change frequency, they're always on a standard musical note. There's one example of that in the video. It's a cute feature, people like it, and it's probably all in software.
They could easily have picked aharmonic intervals, and it would have even been a little easier. But given the opportunity, they chose to make something that added a little bit of color and magic to the world. I love that.
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).
See also: https://www.youtube.com/@yuqquu/videos
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.
I think that's game footage, but not sure what game it is. The train game or sim genre has a bunch of folks who go incredibly deep and accurate in their representations of real trains.
If you want an incredibly detailed 3 hour history of the genre: https://www.youtube.com/watch?v=5vwE_p9SCXw
That’s not a real life video. Is a capture from a train simulator app.
Like Microsoft Flight Simulator, but for trains.
Example: https://www.trainsimworld.com/
Apt example considering that they also released Microsoft Train Simulator in 2001.
Your example is the exact answer.
Simulations have gotten quite good, apparently. It threw me for a loop for a moment, too, until I figured out what was going on.
I believe this is an example of ludonarrative dissonance. The camera is simply at a fixed offset from the train model.
The secret behind this camera is that it exists within a virtual world, and therefore can freely float anywhere ;)
An easier giveaway might be the floating teal icons on the station platform.
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.)
The other problem it solves is the complex transmission required. Diesel-Hydraulic locomotives were built, but were not successful long term. The most famous is the Krauss-Maffei ML4000, built for the Southern Pacific railroad.
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.
Continuing to burn fossil fuels forever isn't really an option. At some point we'll effectively run out, but before then we'll have caused catastrophic climate change due to our CO2 emissions.
Synthetic or plant-based fuels are plausible options, but synthetic fuels can't compare with battery EVs in terms of energy efficiency, and plant based fuels need crop land that's probably better used to grow food.
Electric vehicles aren't a temporary fad. They're here to stay. Liquid fuels aren't going away either, but I expect eventually they'll be used mostly for military and aviation applications, not ground transportation.
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.
The Prius and other HSD cars (i.e anything with a power-split device of the Toyota variety - input-split PSD) are some of, if not flat out the most reliable and simple ICE cars. Permanent atkinson-cycle engine, no turbos because there's no exhaust gas pressure to drive them in the first place (and if there was, it'd be an inefficiency to be rooted out), bulletproof starter/generator especially since the ls600h (double-sided cooling of IGBTs >> no usual IGBT packaging degradation-related failure modes - this was NOT the setup on the 3rd gen prius), still a very efficient power transfer from the engine to the wheels (a big percent is still transferred mechanically), etc, etc.
Adding a bigger battery to those isn't a whole lot of increased complexity. The only issue is making a PHEV that has the same performance characteristics in both EV and hybrid mode - not that it hasn't been done. Specifically on HSD cars, the two electric motors combined, or even just MG2 (the "motor") have way more power than you'd assume - they actually function as an AC-AC converter, converting a significant portion of the engine's output power from mechanical to electric and back to mechanical again. It's essentially the way the eCVT works. Therefore, with a battery (and buck-boost converter) that can support such a load, they can propel the car alone way more than adequately - with a speed limit to protect the "generator" from too high RPM, due to the way the HSD works.
Anyways, it absolutely can be done and it absolutely can be way simpler. If it's a case of a typical modern ICE with a big battery and a motor thrown in somewhere that makes it "hybrid"-ish - i.e. all the ICE complexity + the EV "complexity" (minus the classic starter/alternator) - yeah, no thanks.
IMO: Good examples - the Chrysler Pacifica PHEV. Bad examples - C63 AMG (the PHEV version).
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.
I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card).
But I'm also perfectly happy to admit that it's fine and doable just requires adjustment of expectations, and even the charging network thing I'm sure has solutions if you plan beforehand.
I hear you. This is a choice everyone has to make for themselves. Not everyone will have the same priorities or circumstances.
My longest yearly trip is ~1200km, but that's like once a year. Several times a year I do a 500km trip. On the long haul the additional refueling stops make the trip about 10% longer, on the shorter trip it has more impact, about 15%. Caveat: this is in the western US and superchargers are invariably right next to the freeway, so they don't add much time to the trip.
What really sold it for me was eliminating the trips to the gas station. That is a level of convenience it will be hard to give up.
I'm in the market right now for a new second vehicle, since I'm eliminating the need for a thirsty HD pickup capable of towing our trailer, and what I'm finding is that the market for EVs is not great in the truck space. Couple choices, both with ups and downs, and a little bigger than what I'd prefer (C'mon, Toyota, make us an electric Tacoma). So I'm faced with having to get another ICE vehicle, and the inability to fuel at home bums me out.
I got the tip from other BEV users for charging in Germany to go off the highway and find something like a shopping center/mall. There they had always plenty fast chargers and something convenient to do as well. Their built in navigation showed them the way. (This was bmw, not Tesla.)
I mean, you can use Tesla chargers with any car these days in the EU?
That video turned out way more interesting than I first thought. I never really considered why the 380 makes that noise, i assumed it was a maintenance issue.
Anyone know what the BART FOTF trains use? I’m guessing it’s IGBTs but they sound more like fixed PWM switching to pattern mode with pulse drops.
Can't they filter out those sounds with some L's and C's?
The motor is a bunch of big Ls, and the Cs are already used to feed the chopper.
A class D amplifier + speaker has a very similar circuit topology, yet here we apply filtering all the time ...
Fun and educational video!