I too, can't give an exact date for the last year of steam on the ex-BR&P, though my DVD of The Vanishing American, a filmed record of a steam passenger local on that portion of the B&O, gives 1954 as the last year for regular steam passenger operations, though it's virtually certain that steam proper ended later than that. I plan on attending the B&ORHS 2008 Annual Convention in Butler, PA this fall, and if I find out when the last steam operation took place on this portion of the B&O, I'll hopefully remember to come back here and let everyone know.
Wade Rice
Member, B&O RR Historical Society
http://www.borhs.org
Daniel Willard (1860-1942) and Jervis Langdon, Jr. (1905-2004) - Two of B&O's best presidents and managers!
President Leonor Loree (1858-1940) brought the B&O into the 20th century!