I don't know if this helps for current value, but I bought a set of 5 of these cars (numbers 881 to 885) in 1998 for $320.
Odd you should mention these now because my set sat in storage for years and I just decided to run them on the SD3R layout last Sunday. They are nice cars. I first ran them with a Williams Amtrak FP45 that I got at the same time, but they look better behind a K-Line FP40.