Tweetsie is the name of a locomotive operated at Tweetsie Railroad Wild West Theme Park.

From their website: "Locomotive No. 12 is the last surviving narrow-gauge steam locomotive of the East Tennessee and Western North Carolina Railroad (ET&WNC), which ran train service from Johnson City, Tennessee to Boone, North Carolina from 1919 to 1940."

This bridge probably carried this locomotive in the past.

ETWN - Hampton South Bridge (Carter County, Tennessee)
Abandoned through truss bridge over Doe River on ET&WNC RR (abandoned)