No that was predominantly Biden himself, who issued an executive order to create a presidential emergency board to intervene in the negotiations, and proposed a deal. Union workers did not accept the deal and planned to strike, and Biden requested democrats force the unions to accept the deal and outlaw the strike. Notably, against the wishes of Bernie who opposed the legislation for containing zero sick days for rail workers.
Also notably, IBEW was in favor of that deal from the start, and they are an electrical workers union. They always had the sick days. Not all rail workers got sick days, they didnt get as much as if they had the ability to strike, and most importantly of all lost all of the future leverage that comes with collective bargaining.