HSP-46 now concentrated on South side?

I haven’t heard the ‘whistling’ of an HSP-46 on the Lowell line in a couple of weeks now. And looking at the 8/29 roster on http://roster.transithistory.org I see only 2 on the north side now. I guess Keolis have decided to keep them on the south side for the heavier trains?

The reason that they are south is because they get up to speed faster than the older ones and can pull more cars at ease. They are only sent north when they break down southside.

The fact that, like the K and R cars, the HSP46s have both ATC and ACSES also helps steer them towards the south side. The north side is equipped with ATC, like on the 1500s and 1600s, and GP40MCs. The only reason the K cab cars are going north is [Insert new order of Rotems here]