The depot is still standing at Sparta. It is listed on the National Register of Historic Places, and is currently used as a warehouse.
From the Tullahoma News 11-11-09:
The Railroad Section House Museum in Sparta will be open to the
public next Saturday.
The structure was donated to the Bon Aire Mountain Historical Society
by Carol Blodget MacIntosh of White County. Society Members have
been working since June to restore it.
The section house once sat along a 6 1/2 mile spur connection Bon
Aire to Sparta (NC&StL). Every Day two passenger trains consisting
of two coaches and a baggage car would travel from Sparta to four
local coal towns.
According to the Herald Citizen of Cookeville, it is touted as the
only remaining railroad section house still in its original form.
RAILROAD SECTION HOUSE MUSEUM
of the Bon Air Mountain Historical
Society, 9479 Crossville Highway,
Sparta (DeRossett) TN 38583. Winter
hours: 10 a.m.-4 p.m. Saturday. April 1
and thereafter: 9 a.m.-4 p.m. Friday
and Saturday. (931) 935-6463.