He alleges Alexander Wright was harassing commuters at the Pelham Parkway Subway Station. Nelson stepped in to intervene. That's when he says he was attacked.
"My life was altered for trying to do the right thing," said Nelson.
He suffered a broken nose and collarbone, saying he now does not have mobility of his right arm.
Wright was charged with second-degree assault.
On Wednesday, Alexander Wright appeared in front of a judge at Bronx Supreme Court.
Nelson attended, with the MTA Union standing behind him.
In a prior hearing, he was deemed fit. Wednesday's court appearance would have determined if the case would go to trial.
The possibility of trial still hangs in the balance.
"We want people to get the help they need. We certainly want justice to be served to the full extent of the law. He remains in jail right now, and that's where we want him to remain," said Robert Kelley, vice president of TWU 100.
After almost four years of fighting for justice, Nelson says he want this chapter to be over.
"I can't move forward until this is done... And that's the most frustrating part," said Nelson.
Wright is due back in court Feb. 25.