I'm not sure that's a fair comparison. The original commenter's suggestion was to "modernize" a train route that runs near their campus. My assumption is that the route is currently functional, only missing the required stations and amenities necessary for relatively short-term passenger transport. I don't think high speed is called for in that situation, just anything capable of making a commute more bearable and less costly, therefore a conventional passenger train would likely suffice.

Additionally, it would still be a primarily municipal project, for which Facebook (and perhaps other interested private parties) would only partially contribute to in monetary terms.