PLEASE VIEW MY BOSTON & ALBANY STEAM LOCOMOTIVE WEBSITE. IT HAS 279 PHOTOGRAPHS OF B&A STEAM ORGANIZED BY TYPE. THERE ARE 19 WHEEL ARRANGEMENTS INCLUDING 2-6-6-2's, 4-8-0's, 2-10-2's, 2-6-6T's, K-6's, H-10's,etc. (QUITE A VARIETY) CLICK http://sites.google.com/site/bostonalbanyrailroad
The B&A 2-6-6-2s migrated west to the NYC's Pennsylvania Division for a while. Some were used as pushers for "downhill" run from Cherry Tree to Mahaffey on the Beech Creek District.
Why pushers for a downhill run? Curves, lots of them. All those curves added enough resistance to pulling a loaded train that pushers were needed, going downhill no less.