Having been a B&O fan since 1962 (birth year) I have a few suggestions for steam power.
Some of the last B&O steam locomotives were the T-3 4-8-2s built from '44 to 48 at Mt Claire shops in Baltimore.
Westside imported these in the mid 80s, and are very nice runners.
A passable Pacific can be had from a Tyco/Mantua unit, the cab profile is not right, and msot B&O 4-6-2s had high mounted headlites, but they are passable.
In the late 50s, Gp7s and 9s wer common as well as F units, from FTs to F-7s.
Heres some recomended reading;
B&O Power
Slagle and Stouffer.
excellent book on the road, from it’s begining in 1827 to the early 1960s
B&O locomotives, the last 25 years.
TLC publishing
Smaller version of B&O Power, some photos are a little muddy, but servicable.
Thunder in the Alleghenies
Carstens, by Deane Mellander
Out of print for many years, but recently back from Carstens. Good, action photos, of late steam in action.
B&O in the Potomac Valley,
Kalmbach, Martin McGurk
Another good monograph, although the location of Sand Patch is wrong in several maps and graphics.
Impossable Challenge, East End, West End, and Sand Patch Clash of Titans
Charles Roberts, publisher
Authors Roberts, Hollis, Harwood.
The complete reference for fans, a four book set can be pricey, but well worth the money. Complete from Baltimore in 1827 to Grafton W.Va and Connellsville Pa. 1993.
The History of the Baltimore and Ohio Railroad
John Stover
Perdue University press
The definitave reference for all things B&O business history.
Good, but dry.
Hope this helps