Due to the recent B&M/PAS derailment in Charlemont, MA, some of their trains are being rerouted on the B&A to Worcester then up the branch to Ayer. The first of these reroutes is train X800 (22K) seen here at MP57 in Charlton, MA with CSX 8842 leading NS 7663, NS 8030 and NS 9895 pulling 380 axles.
Update - this ended up being the only PAS reroute due to the quick cleanup in Charlemont. Interesting to note that this train was all single stacks due to the original Hoosac Tunnel routing whereas normal traffic on the B&A is mainly double stacks.
5/16/2016 - 598C7954dK