I鈥檓 surprised it鈥檚 as little as that. My understanding of trains is that the rolling resistance is very low and that all the energy is really for accelerating from standstill. That would be recovered during braking (mostly).
Cabin climate and lighting, especially in warmer contries must be a good 10-20% of energy usage. But yeah a lot of energy is wasted into heat, the London underground is a perfect case study on it
I am now genuinely curious about the challenges of insulating things underground. Do you know a good article or a study that I can read?
I鈥檓 amazed that they only learn about this now. Using regenerative braking on trains was something we got taught about in school, and that鈥檚 nearly 40 years ago.
Until fall 2024 Caltrain ran on diesel engines. It just electrified so I don鈥檛 think returning energy was feasible for the line until just recently.
How would they learn that the newly installed system is more efficient than predicted before now?