TN 48 Business in the HB is signed as mainline TN 48 and what TM has as TN 48 through central Dickson is TN 48A.
There are multiple TN 48 ALTERNATE postings (summer 2019 GMSV) and mainline 48 is posted on TM's TN 48 business. TN 48A appears on county maps back to at least the late 1970s.
This is an odd setup to have by TDOT, as TN 48 has a section south of US 70 Business that can only be driven SB, so they should have TN 48 on one-way splits or similar.