I suspect that the biggest reason for the low fare evasion rate on Caltrain is that the line serves a relatively-wealthy clientele for whom the fare isn't a bur

I suspect that the biggest reason for the low fare evasion rate on Caltrain is that the line serves a relatively-wealthy clientele for whom the fare isn't a burden. Many of Caltrain's patrons even get subsidies from the companies they're commuting to. Interestingly, until recently fare evasion on Caltrain was a criminal infraction. In the past few years, Caltrain has moved to a flat $75 civil penalty instead (like a parking ticket), which I believe ended up earning Caltrain more money overall because it's less hassle for conductors.