Found these cars to be interesting. Decided to collect them.
So far I have:
K-515708 - K-Line Loves New England Boxcar
K-515802 - K-Line Loves America Boxcar
K-641-740801 - K-Line Loves Chicago Boxcar
K-641-740802 - K-Line Loves New York Boxcar
K-641-740803 - K-Line Loves Philadelphia Boxcar
K-641-740801 - K-Line Loves Los Angeles Boxcar
I'm looking for any other in the series - but NOT the individual state cars (got plenty of those from other manufacturers).