I simply could not figure out how to get the Anaiis software installed so never got the Subway working on the A500 with WB2.1.
More easier, you die...
go on aminet, type anaiis and download the anaiis.lha, extract files on a real amiga...
copy bin/anaiis and bin/usbstart and their icons where you want on a disk, and that's all.
If the clockport base address is not 0x00d80001, you should select "Subway" in the preferences/system tab of ANAIIS program and put the real clockport base address in Param1.
At this step you can use keyboard, mouse, printer (usbprint), paddle (playhid) and disks (massive)
Don't give up :-)