I've read the B&O wasn't running steam, at least on passenger trains, in 1959. Then I found this: http://www.sessions-station.com/B%20&%20O%20Railroad/B_O5222_4-6-2BakerstownPA45mph2-12-59HNewlonJrJSFcoll.html northeast.railfan.net/images/bo5222s.jpg (you can start the link yourself, the site is doing that error again where I can't post complete links) was labelled as "Bakerstown PA, 1959". Was this engine in excursion service? I notice it doesn't have a 3-digit number like other B&O steam got in 56-57.
I'm pretty sure that the last steam in "regular" service on the B&O was in April of 1958. B&O did sponsor some steam powered excursions after this, so that may explain it.
It wouldn't be an excursion. That is a mail train. There were odd instances when steam was pressed into service durring a power shortage but I don't know if that explains this or the date is a typo.