It seems like a lot of investment for a minimal gain, but as Nikkei makes clear, being able to send trains between the stations at 130 km per hour, as opposed to the current limit of 110 km per hour, is important. It's currently around a 30-minute trip between the two. "Even reducing the time by a minute is a big step towards increasing passenger numbers," a representative told Nikkei.
Residents in communities surrounding the tracks are concerned about vibrations and noise from trains on this stretch of the line, which is why there is currently a speed limit in place. JR East hopes that by installing additional sound absorbing paneling, the noise will be low enough to where they can increase train speed through the corridor.
It's quite a bit of work for what seems like marginal benefits, but the company has been searching for a solution to this issue for a decade. The Japanese railway system is the envy of the entire world; projects like this will ensure it stays that way.