Freeways vs rail is a false dichotomy. The best transit systems are multi-modal for different needs, and those things do serve different needs. What we're really talking about is establishing rights of way. Once you have those it's usually no harder (politically) to build one type of artery alongside the other, like how BART's Concord and Dublin lines were built in the medians of the existing CA-24 and I-580, respectively.