Maybe I'm misreading the tea leaves but two recent events re: Pan Am Railways locomotives make me wonder how serious NS is about acquiring the PAR balance of Pan Am Southern:
1.) PAR's recent acquisition of 20+ relatively young ex-CSX C40-8 locomotives: If NS were thinking of taking 100% control of PAS track and rights from CPF-312 west, then NS would have dipped into their stored road / yard locomotive pool to bump PAR's tired GP40s and SD40s out of E Deerfield to points east of Ayer, meaning that PAR might not need to acquire the C40 units. Replacing PAR hardware with NS hardware would permit 30 (my guess) or so engines used on the freights that depart or terminate at E Deerfield to be deployed to PAR ops.
2.) NS/PAS recently sent a letter to the STB complaining that MBTA was no longer intending to install PTC on 92 PAR locomotives per a 2014 agreement signed by Beverly Scott and Dave Fink Jr. If NS were intending to acquire all of PAS, all locomotives used west of CPF-312 would be NS and likely be PTC-equipped (many NS engines in use already have PTC gear installed), meaning only PAR freights east of Ayer and Boston area locals would need PAR locomotives equipped with PTC (numbering far less than 92 units). If PAR got into a bind on PTC cut-in date, use of NS locomotives on EDPO/POED and CSX locomotives on SEPO/POSE could be contemplated but obviously some other arrangement would need to be made for Boston area locals. And unrelated to the NS question, why is CSX not a supporter of the complaint to the STB re: MBTA's alleged backing away from the 2014 agreement, given their Maine and Boston area interchange business is exposed?
Anyway, please feel free to set me straight here...