N&W MofW Ballast Car 544000

[nw-mailing-list at nwhs.org]

At the bottom of page 126 of the N&W Color Guide to Freight and Passenger 
Equipment, there's a photo of N&W 544000 taken in 1984.  It is a photo of a 
ballast hopper converted from a covered hopper in 1982 by removing the roof 
and adding appropriate discharge chutes.  The text accompanying the photo 
also states that the car comes from the N&W HC8 class (former series 
71350-71425, built by ACF in 1958/59).

What I'm unable to discern from the text is whether this was a singular 
conversion, done as a feasibility test for extending the life of the HC8s 
(if the car shown were any number other than 544000, I might not be asking) 
or whether all 75 HC8s received this same conversion to ballast cars?

Any ideas as to approximately how long this car (or all of them, if so 
converted) lasted in service on NS's roster?  I know N&W (NS) received some 
new ballast hoppers in the mid-'80s, so I'm not sure if those new cars would 
have done in the older converted car(s).

Thanks for any insight!

Scott Marion
Winston-Salem, NC