WASHINGTON, Nov 5 (Reuters) - A labor union representing about 4,900 rail workers said on Saturday that members narrowly ratified a tentative contract agreement with freight railroads in the United States.The International Association of Machinists and Aerospace Workers (IAM) District 19 said 59% of the membership voted and it was approved by 52% of voting members after an initial unsuccessful ratification attempt last month.The National Carriers’ Conference Committee (NCCC), which represents freight railroads in labor talks, said unions "have repeatedly agreed that short-term absences would be unpaid in favor of higher compensation for days worked and more generous sickness benefits for longer absences."Last month, the Brotherhood of Railroad Signalmen (BRS) union, representing more than 6,000 members, voted against the deal as did the Brotherhood of Maintenance of Way Employees (BMWED), which represents 11,000 workers.Last week, more than 300 groups including the National Retail Federation and National Association of Manufacturers on urged President Joe Biden's involvement to help avoid a potential rail strike."