Ralph and group,
Yes it is the BCW #27 70' Clerestory roof.
I have yet to measure the window sizes between the M70 & M70A. Will do that Monday at the earliest. Of course I will measure the Rivarossi windows also for comparison. Remember the M70A was built by ACF so there is a good chance the windows are different sizes.
What I really need to do is scan the diagrams from Rob's Pennsy page or the Keystone and scale them for HO.