The Roanoke River Bridge in Weldon has always been a single track structure and was one of only several single track sections between Richmond, VA and Savannah, GA. Other single track segments included:

Appomattox River - Petersburg, VA (A23.0 to A23.3)
Pee Dee River - Pee Dee, SC (A280.2) to WN (A282.2)
Santee River - Santee Bluff, SC (A345.0) to Etta (A348.4)
Savannah River - Sand Island, SC (A477.8) to Chatham, GA (A480.8)