At some long ago celebration, probably 1940s. Any guesses where or when?

http://abpr.railfan.net/abprphoto.cgi?j ... anColl.jpg

Bob,
The smiling face of EM-1 # 7605 at the left helps a bit. She was built sometime in late 1944 so it had to be after that. The large modern engine in the background whose skyline profile you can see has me a bit stumped. The features don't quite match any larger, later B&O engines. So if it is indeed another road's engine, it would make sense that the gathering was a multiple corporation event. Which would lead me to believe it could be the 1948/1949 Chicago Railroad Fair. The B&O as well as 21 other class 1 roads, 9 terminal railroads and 3 interurban lines served Chicago at the time and it was the last big rail industry show of it's kind. So now, what engine is that in the background??