I was stumbling through the web and found this compilation of info and pics on the Martinsburg West Roundhouse (B&O). After a quick google search, I'm glad to know that this structure is still standing.
Anyways, here's the link, and there are some pretty nice pictures in the /photos directory. (look at the .jpg files) The text descriptions are in the .gif files in the /data directory and there are also drawings in the /sheet directory.
By digging through the base directories, I've found lots of rail related sites. Neat stuff!
JimE
HAER info on the roundhouse
jrevans@accusort.com