> Thank you. I don't have access to a PC with a floppy drive. I will look into your > other suggestions.
You don't have a PC with a floppy drive but you can emulate a PC in MAME with a floppy drive.
The point is theoretically you could load the files to an emulated IBM PC machine and then copy them to a formatted RX50 floppy image using the DOS driver.
My experience doing that kind of things vary though. I can't simply create a floppy disk image with IsoBuster then expect it to be read by MAME right away, I ended up with read/write errors. I would have to create a blank disk into MAME, format it with DOS into MAME and then use the resulting blank disk image to inject external files using IsoBuster.
I would try creating a formatted blank disk on Rainbow 100 and then use that blank disk image to copy external files on an emulated IBM PC environment. You could also start by trying to read a softlist .TD0 disk on an ibm5170 machine with the DOS RX50 driver.