CW Tower- another milepost question

[nw-mailing-list at nwhs.org]

CW Tower in Columbus,OH is where the PRR Sandusky Line was grafted onto the 
N&W during the 1964 merger. The N&W mileposts ran toward downtown, following 
the passenger main, which apparently ran through the middle of Joyce Avenue 
Yard. (My source here is a 1977 track chart.) It looks like N-705 was the 
last milepost going toward downtown. The N&W started new mileposts for the 
Sandusky Line at CW Tower (N-704.6), making it S-1.0. Why didn't they start 
at S-0.0? One mile east of CW was in the middle of Pennor Yard. If I 
remember right, the PRR mileposts were different, and N&W started fresh with 
new ones. Maybe I am wrong on this, and they just adopted the PRR mileposts. 
Anyone have any answers on this? - Keith Baker, Ft. Wayne,IN