For regional transit, China's high speed rail buildout [1] is truly breathtaking. If you look at the miles of track [2], China has 45000km with 25000km under construction. Number 2 on the list is Spain (with 4000 and 1000 respectively).
For urban transit, China again completely dominates [3] by like a factor of 6-7 to #2. The US actually fares better here bu that's skewed by a handful of outliers, most notably NYC.
It makes me so mad because of the concerted effort made to dismantle and derail (pun intended) public transit efforts in the United States. The Koch brothers (well, brother) spend a fortune fighting these projects [4]. Elon Musk famously only propsosed the Hyperloop in the hopes of killing the California High Speed Rail ("HSR") [5].
Look at Las Vegas, a huge tourist destination. What Las Vegas actually needs is a subway line between the airport and the major Strip hotels. This would require probably less than 20 miles of tunnels. It could even be a mix of light rail in the suburbs and to the airport and tunnels under the Strip. You could extend it to key parts of Las Vegas to include all the people that need to work on the Strip through Park and Ride stations. It would be incredibly cheap for the benefit.
But instead we got the idiotic Tesla tunnels by The Boring Company, which I'm convinced was only proposed to kill the idea of any public transit infrastructure in Las Vegas.
It's all so short-sighted because public transit scales and it would make life easier for anyone who actually wants or needs to drive. But instead we get idiotic infrastructure like the Katy Freeway in Houston [6].
[1]: https://www.reddit.com/r/MapPorn/comments/xszhbm/chinese_hig...
[2]: https://en.wikipedia.org/wiki/List_of_high-speed_railway_lin...
[3]: https://en.wikipedia.org/wiki/List_of_metro_systems#List_by_...
[5]: https://twitter.com/parismarx/status/1571628269555826688
[6]: https://b93.net/widest-freeway-in-the-united-states-is-in-te...