Hi Cindy, as a matter of fact, I've recently put together a list of those from the 13th NC that were captured "on the South Side RR", and sent to Hart's Island. I'm not good at all with military terms and strategy, but the South Side RR I believe, was the only railway open to Lee's army. That would explain the effort made to defend it. I'm also thinking remnants of the 13th were probably a part of the Confederate force that tried to make a stand at Sutherland Station following the breakthrough on April 2nd. Here's some other info I have at another sight that might interest you :

https://civilwartalk.com/threads/confederate-p-o-w-s-on-harts-island-are-told-of-lincolns-murder.132156/

https://civilwartalk.com/threads/the-rebel-prisoners-at-harts-island-my-2nd-great-grandfather-was-among-them.100915/#post-893500

https://civilwartalk.com/threads/the-rebel-prisoners-at-harts-island-my-2nd-great-grandfather-was-among-them.100915/

I believe I've seen a post-war photo of your husband's ancestor somewhere, but it's been years ago.

Private William Allen, Company C from Caswell County

Private Lindsey Andrews Company D from Henderson County

Sergeant James M. Benton Company I from Rockingham County

Private John M. Campbell Company D from Union County

Private Milus Deal Company I from Wake County

Private J.E. Hinton Company K from Rockingham County

Corporal David Land Company I from Wilkes County

Private Lindsey George Lewis Company B (residence unknown, also had service in 63rd Cavalry)

Private James R. Medford Company G from Edgecombe County.

Private Josephus Pratt Company I from Rockingham County

Private Calvin Sharp Company H from Rockingham County

Private James Tulloch Company K from Rockingham County

(Captured 4/2/1865 at Battle Of Sutherland Station)

Private Irvin T. Harris Company G from Edgecombe County

Private David McCollum Company I from Rockingham County

Private John S. Park Company A from Caswell County

Private John Elijah James Winchester Company I from Rockingham County