Well, here we go with the HAER (Historic American Engineering Record):
General Page:
http://memory.loc.gov/ammem/collections/habs_haer/
Results for a search of "Railroad" (only 1,979 items):
http://memory.loc.gov/cgi-bin/query
Narrowing down to "Baltimore & Ohio Railroad:"
http://memory.loc.gov/cgi-bin/query
Going through the list (and one could also narrow the search, as in "Martinsburg, W.Va."):
http://memory.loc.gov/cgi-bin/query/D?hh:41:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&fileName=wv/wv0200/wv0257/photos/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20Machine%20Shop,%20West%20Side%20of%20Tuscarora%20Creek%20Opposite%20East%20End%20of%20,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&itemLink=D?hh:41:./temp/~ammem_X5nl::
East Roundhouse (now in ruins following a fire some years ago):
http://memory.loc.gov/cgi-bin/query/D?hh:62:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=wv/wv0200/wv0256/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20East%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&maxCols=2&itemLink=D?hh:62:./temp/~ammem_X5nl::
The west house, still standing:
http://memory.loc.gov/cgi-bin/query/D?hh:77:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=wv/wv0200/wv0255/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20West%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&maxCols=2&itemLink=D?hh:77:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&action=browse&fileName=wv/wv0200/wv0255/photos/browse.db&recNum=0&itemLink=D?hh:77:./temp/~ammem_X5nl::&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20West%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1
Other now gone facilities, in this case, at Cumberland, Md.:
http://memory.loc.gov/cgi-bin/query/D?hh:78:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=md/md0000/md0001/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Bolt%20%26%20Forge%20Shop,%20Spring%20Street,%20Cumberland,%20Allegany%20County,%20MD&displayType=1&maxCols=2&itemLink=D?hh:78:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&action=browse&fileName=md/md0000/md0001/photos/browse.db&recNum=0&itemLink=D?hh:78:./temp/~ammem_X5nl::&title2=Baltimore%20%26%20Ohio%20Railroad,%20Bolt%20%26%20Forge%20Shop,%20Spring%20Street,%20Cumberland,%20Allegany%20County,%20MD&displayType=1
Came across the now-gone facility at Keyser, W.Va.:
http://memory.loc.gov/cgi-bin/query/D?hh:68:./temp/~ammem_X5nl::
I'll leave it to the readers to look for more material, including that from other roads that may be their favorites.
Good luck and good hunting!
General Page:
http://memory.loc.gov/ammem/collections/habs_haer/
Results for a search of "Railroad" (only 1,979 items):
http://memory.loc.gov/cgi-bin/query
Narrowing down to "Baltimore & Ohio Railroad:"
http://memory.loc.gov/cgi-bin/query
Going through the list (and one could also narrow the search, as in "Martinsburg, W.Va."):
http://memory.loc.gov/cgi-bin/query/D?hh:41:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&fileName=wv/wv0200/wv0257/photos/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20Machine%20Shop,%20West%20Side%20of%20Tuscarora%20Creek%20Opposite%20East%20End%20of%20,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&itemLink=D?hh:41:./temp/~ammem_X5nl::
East Roundhouse (now in ruins following a fire some years ago):
http://memory.loc.gov/cgi-bin/query/D?hh:62:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=wv/wv0200/wv0256/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20East%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&maxCols=2&itemLink=D?hh:62:./temp/~ammem_X5nl::
The west house, still standing:
http://memory.loc.gov/cgi-bin/query/D?hh:77:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=wv/wv0200/wv0255/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20West%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1&maxCols=2&itemLink=D?hh:77:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&action=browse&fileName=wv/wv0200/wv0255/photos/browse.db&recNum=0&itemLink=D?hh:77:./temp/~ammem_X5nl::&title2=Baltimore%20%26%20Ohio%20Railroad,%20Martinsburg%20West%20Roundhouse,%20East%20End%20of%20Race%20%26%20Martin%20Streets,%20Martinsburg,%20Berkeley%20County,%20WV&displayType=1
Other now gone facilities, in this case, at Cumberland, Md.:
http://memory.loc.gov/cgi-bin/query/D?hh:78:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhsheet&fileName=md/md0000/md0001/sheet/browse.db&action=browse&recNum=0&title2=Baltimore%20%26%20Ohio%20Railroad,%20Bolt%20%26%20Forge%20Shop,%20Spring%20Street,%20Cumberland,%20Allegany%20County,%20MD&displayType=1&maxCols=2&itemLink=D?hh:78:./temp/~ammem_X5nl::
http://memory.loc.gov/cgi-bin/ampage?collId=hhphoto&action=browse&fileName=md/md0000/md0001/photos/browse.db&recNum=0&itemLink=D?hh:78:./temp/~ammem_X5nl::&title2=Baltimore%20%26%20Ohio%20Railroad,%20Bolt%20%26%20Forge%20Shop,%20Spring%20Street,%20Cumberland,%20Allegany%20County,%20MD&displayType=1
Came across the now-gone facility at Keyser, W.Va.:
http://memory.loc.gov/cgi-bin/query/D?hh:68:./temp/~ammem_X5nl::
I'll leave it to the readers to look for more material, including that from other roads that may be their favorites.
Good luck and good hunting!