I live (mostly) in Germany. But as I've said, when you zoom out and look into it, considering all that goes through and into it, it seems like it.
No matter where. ISTR tidbits from documentaries, many websites specializing in analysis, even wikipedia. Especially that rail thing, only one third from power plant reaching the locomotive is normal.
Let's put it this way: You have a model for your use case, a (mind) map. But the map is not the territory :-)
Link please. Because that would be a terrible performance figure for a high power system like that. Worst possible loss figures I've been able to find for our grid are 15% losses between the power plant and the plug, and that's including the losses in low-voltage distribution (400 V 50 Hz three-phase). Modern rail runs at 25 kV/50 Hz single-phase. 66% losses would be mind-boggling. As per [1], the expected losses for powering 25 kV rail are around 7% including conversion between transmission lines and the traction lines. So even including losses between the power plant and the conversion substation, they should definitely be significantly below 20%.
[1] https://vts.cd.cz/documents/168518/195369/3201.pdf/9a95e429-...
Mission impossible for now, because sleep is long overdue. Anyway, something anecdotical: At the times, when I looked into it about 2008, I discussed that with some people, some of them 'engineers', as in the people who actually drive the trains (both freight and passenger). They also confirmed that, they even learn that during training. Can 15kV at 16 2/3Hz produce such differences?
Whatever, as I said before, it isn't limited to rail, grids as they are now aren't as efficient as the models suggest. But I can't re-research this at the moment. I just know I didn't hallucinate that stuff, OK?
That's not how it works because it's assuming a point to point connection for your use case. In reality there is the grid, and from everything I know transmission losses from whichever source to your socket over that grid average out to 50% best case, to about only one third reaching the destination. The latter for instance for electrified rail.