I have a Warren, PA collection, also not a difficult note to find and it's close to Pittsburgh.  I like first name towns although the town was named for a general with a last name of Warren.  For Charter 4879, there are at least two Cashier/President signature combos (R.W. Mackay and F.E. Hertzel; N. C. Gill and F.E. Hertzel) on series 1902 PBs.  I only have a $5 note in a PMG holder; it's in a signature set.  I plan to submit at least the $10 one day.

Very nice!! I bought my Warren simply because I couldn't believe I found an NBN in 25EPQ!!

I picked up some more Warren's Type 1. I hoe I am not stomping on your territory. I like the way Hertzel's signature has 3 dots below the signature line on the large and small types. Very easy to recognize. 

The Warren National Bank was a prolific issuer for a small Western PA town.  My wife has to convince me that I can't own them all.  For some reason it took me 7 months to see your notes posted here--quite nice!  I'm looking for a Type 2 on Charter 4879.  My recent submissions just moved up one notch in the PMG queue for grading.  They may be home before the new year (and posted to my signature set on the Warren NB.