Thanks for the info. I thought this might be unusual because of the intense interest being given this train on Facebook. It seems to be a really big deal there that went beyond the BNSF pumpkins.
This is the first Ardent Mills-bound grain train to be operated by B&E over PAS from RJ to Ayer (in fact, I think its PAS symbol was RJAY). Previous unit grain trains unloaded at Ardent Mills by B&E crews came via the B&A and the Worcester main and generally had the BNSF power removed at Selkirk in favor of a CSX unit leading other CSX or Pan Am power.
For RJAY, the BNSF units ran uncapped east to E Deerfield where BERX C40-8 #7489 was added ahead of the BNSF power to provide cab signals and ACSES PTC to get through MBTA territory. RJAY dropped half its train on the Camp track on Friday night and the BERX + BNSF power set took the first half to the Millings and started unloading at around 0730 Saturday. Unloading the first half took approximately 6 hours and the crew spent another hour re-arranging the BERX unit to lead the empties west to Ayer with another crew.
In general, foreign power has become rarer in Ayer due to the need for PAS/NS to use power sets swapped out at Binghamton led by SD60E ACSES/I-ETMS units on its 264/265 intermodal trains (which quite often feature BNSF or UP power west of Binghamton) and 16R/11R manifest trains.