the more I think about it, the more convinced I become that there are little downsides to the idea besides the initial costs of solar panel production, dismantling a significant portion of the existing highway infrastructure in the US, and then actually laying the rail lines (building stations as well, I guess) and the panels.

Like, what you spend in funding, time, and manpower you make up for with reduced emissions, significantly increased public access to transportation, more green spaces in urban/rural areas where highways cut through them, etc etc. goddamn