I'm looking to create some custom decals to model the Japanese passenger cars operated by the U.S. Army, during the occupation, 1945 - 1952. I've found commercial fonts very close to the ones used for the English text on these cars, but nothing to represent the Japanese Katakana type codes and numbers. I did however find a set of outlines for these characters, in a site called "Rail CAD". Using this data, and a font editor program, I was able to create a reasonable font containing most of the Katakana characters, and all 10 single digit numbers. You can download this from:
JNR Font on Dropbox
I've included a PDF with the key mapping for the Katakana, as well as descriptions of their usage in car type markings.