Is the "electric" part of the diesel electric a commoditized technology? Is it a single motor or one per axis?
How expensive is a 10MW electric motor? Asking for a friend
Edit: for context - Tesla Semi is just 4x 250kw motors
How expensive is a 10MW electric motor? Asking for a friend
Edit: for context - Tesla Semi is just 4x 250kw motors
Not really. You can't use the electric side of a locomotive drive train anywhere else than in a locomotive, and for fully electric locomotives you can't even use the transformers in any non-railway setting simply because the frequencies used are generally incompatible with usage on the normal power grid. Old electric locos sometimes are used to provide auxiliary power for parked cars [1], though that has fallen out of fashion here.
What is commoditized is the engine side of a diesel locomotive, that's your run-off-the-mill CAT, MTU or whatever industrial diesel engine. As long as it fits into the locomotive body and accepts a hydraulic or electric generator at the output, it can be used. IIRC there even were some experiments with gas turbines on French high-speed locomotives, but these had atrocious fuel economy.
> Is it a single motor or one per axis?
That entirely depends on the engine model, and can be inferred from the wheel arrangement code [2].
[1]: https://de.wikipedia.org/wiki/Trafostation_(Elektrolok)
This is a surprise, because it calls to mind this old story:
https://gizmodo.com/that-time-a-canadian-town-derailed-a-die...
Was this simply an unusual locomotive, and therefore compatible with the grid? What's going on?
From the article it sounded like it wasn't ideal(there was damage to the gearbox from driving the engines down the road).
(as an aside this is why I think a diesel-electric tractor or pure electric would be pretty nifty thing)
Electric motors on tractors are an absolute rarity (usually, the motors need cooling, which is in conflict with the wheel/tracks being rated for driving through water and mud).
The usual is either direct drive or using the hydraulic generator for the power tools and actuators also for the drive train... and you can get electricity generator packs that you can simply plug in into the hydraulics port for a power tool [1].
[1]: https://hk-hydraulik-kontor.de/de/147440-Hydraulik-Generator...
In this case they took MLW M420W locomotives and just straight hooked them right up to the local grid.
The traction of a DC drive vs AC drive is significantly different(the below article cites at least 2x better for AC) in part due to the fact that a DC motor will "run away" once it breaks the static friction limit where a VFD(holding a fixed frequency) will self-correct as the wheel overspeeds and is slowed down by the other side of the magnetic field. Since most EVs use AC VFD a lot of that same development can be applied in traction applications.
[1] http://www.republiclocomotive.com/ac-traction-vs-dc-traction...
This locked-together wheel drive is a huge win. No more wheel slipping and spinning. Wheel slip has been a huge headache with locomotives back to the steam engine era. The effect is to almost double drawbar pull. Starting heavy trains on upgrades now works much better.[1]
There are many other classic ways to build locomotive drivetrains, but this won out.
UP 4014 "Big Boy", biggest working steam locomotive: 135,375 pounds tractive effort.
General Electric ES44AC, common road locomotive today, over 3700 units built: 183,000 pounds tractive effort.
Dull, boring, from old companies, and very effective.
[1] http://www.republiclocomotive.com/ac-traction-vs-dc-traction...
https://www.up.com/aboutup/special_trains/gas-turbine/index....
A bit off topic, but I find it mildly amusing that most of the article is taken by the huge table that is entirely about steam loco wheel arrangements, and moreover all of those various arrangements actually have their own article! Rather thorough for a decidedly obsolete technology.
The diesel prime mover is usually an EMD or Wabtec/GE engine in the US - very few mainline locomotives use anything else. They are medium-speed engines and two-stroke (EMD) or four stroke (Wabtec/GE with some EMD Tier-4), built to be reliable, cheap and nearly indestructible. You can swap other engine makes in, but usually with worse reliability and performance.
Outside the US other engine makers are more prevalent, but interestingly US engine designs are the most numerous (except in former Soviet states and China). In the US, newer non-road engines may use Tier-4 MTU or CAT engines for eco friendly power, but they're still the exception and not the rule.