Recently I spotted DF4 4002 on a freight on the Fuxin-Shenyang mailnline.
The loco is painted in dark blue, like the early DF4Cs, but uses an ordinary
DF4B hood. I mistook it for a DF4B first as from a distance the dark blue
resembles their usual dark green livery. I assume that it is DF4C prototype
version. It is marked (as usual) only as DF4.

Other trains seen on this line were green DF4B on freights, orange DF4B on slow
pax and red/cream DF4D ond fast pax.
Peter