Why? Because it's a route used heavily by commuters. It connects Sacramento (and parts north) to the Bay Area. The authority estimates 60 percent of riders carry laptops and and half have mobile broadband cards or dongles. (I love that the reporter calls them "air cards," which is both quaint and misguided. Sierra Wireless's modems are called AirCards—brand name—and somehow a decade ago that became the default and weird term for 3G modems.)
Service will be installed during 2011. One rider questions the nearly $4m being spent on the service, wondering if it could have been put to better purposes, such as better wheelchair access. That's a good question, but the point of Internet access is to bring more passengers on board. Train service is subsidized, of course, just like roads and airports, but adding passengers increases costs slightly relative to the additional revenue. If Internet service adds tens of thousands of additional trips per year, this can offset its cost.
The story misses a secondary point: the $4m is nearly the full capital expense for both passenger access and back-end operational uses, which incur separate costs—or simply don't exist, reducing efficiency or safety—today.
Amtrak Cascades Run Gains Free Wi-Fi