This comment is so disingenuous. Your link said guaranteed sick leave was the sticking point in December 2022:

The initial agreement brokered by the Biden administration was accepted by all but four rail unions, who were holding out for guaranteed paid sick leave days. The opposing unions, though, represent the majority of rail workers. The workers and companies had until Dec. 9 to reach an agreement before they vowed to strike, which the industry estimated would cost the U.S. economy $2 billion per day.

But five months later, it was resolved:

When Joe Biden and Congress enacted legislation in December that blocked a threatened freight rail strike, many workers angrily faulted Biden for not ensuring that the legislation also guaranteed paid sick days. But since then, union officials says, members of the Biden administration, including the transportation secretary, Pete Buttigieg, and labor secretary, Marty Walsh, who stepped down on 11 March, lobbied the railroads, telling them it was wrong not to grant paid sick days.

https://www.theguardian.com/business/2023/may/01/railroad-workers-union-win-sick-leave

What do you think this link proves exactly?