why is it surprising ? You have to maintain thousands of miles railroad infrastructure, that includes r.r bridges, train stations, r.r. tracks and trains themselves.
I kinda do see myself surprised.
Air travel is subsidized, airlines pay to use but do not pay for airports. Highways and gas are subsidized, drivers pay tolls, but drivers and car manufacturers don't have to directly pay for all road maintenance. Railways are subsidized, but nowhere near to the same extent.
The Federal government has subsidized Amtrak 30 Billion over the last 30 years. It's subsidized freight rail some, and Amtrak and other services can use those rails, but freight trains have priority. It's subsidized air and highway travel by 1.89 trillion, including around 1 trillion to build most of the airports you see today.
I think it is that the tracks are monopolized.
If you look at freight trains compared to trucking, trucking is less efficient, has higher fuel costs and is cheaper because of competition.