Hafner did not sell anything but passenger cars/sets for almost their first ten years of operation. when they finally started to feature freight cars, they went to Bing who was already supplying them with some accessories and stations.
in the Doyle text there are only nine Bing freight cars listed as supplied by Hafner, but there were at least twice that many Bing independently released into the US market which are definitely compatible. here are a few of my favorites that were in the Hafner catalog...
notice that the US market cars all feature the sinple tab/slot coupler as opposed to their European models. not sure if there is a name for those hook/ loop type.
they also fit in very well with the early Flyer 5½" freight cars...
i have a few cabooses which are also compatible with this 4wh size, but one Bing/ Hafner car which still eludes me is the Bing NYC&HRRR caboose.
cheers...gary
