I assume that the trains extended to Greenfield will have an extra car on them for the extra ridership?
Actually, let me rephrase that: All Amtrak trains along the line need an extra coach on them. The busiest trains of the day for commuters going to New Haven (or Hartford, for points along the northern part of the line) are both 2-car Amfleet shuttles, not 4 car MBBs. Not only that, but the Amtrak trains have higher ridership anyway, since they have been around and used by commuters for years and are faster and more comfortable than the CTrail trains. More people already use the Shuttles, and there will be another boost of ridership when you have more people riding from the busy towns of Northampton and Amherst.
TRAIN(geek) APPROACHING, PLEASE REMAIN BEHIND THE YELLOW LINE