North Somerville Junction and Rule 261 on the Lowell Line

On the off chance that there are other rail signal geeks in Boston that actually read this, the bridge on Broadway over the commuter rail near Ball Square has long been one of my favorite signal spots, since from there there's pretty good visibility outbound and you can see the interlocking signals protecting North Somerville Junction. A month or two ago they turned on new bidirectional signals north of here on the Lowell line, which means trains can run both directions on either track. I'm not sure why but they're pretty actively using it and I've definitely seen approach medium displayed on both tracks (sometimes at the same time even).

(I thought I had seen medium approach medium displayed here driving past once but I wasn't 100% sure. It'd be exotic but not inconsistent with the B&M lines' use of "approch medium" to mean "advance approach"; any confirmation? That would be red, yellow, green reading top-to-bottom on one signal, the other would necessarily be red, red, red.)