Members of the United Transportation Union have approved a new national agreement with major US freight railroads after 3 1/2 years.

The UTU joined 11 other unions that had already reached final agreements on new contracts. The UTU, which represents nearly one third of the rail workforce, has been in negotiations with the National Carriers Conference since November 2004.

The International Association of Machinists is the only rail union that does not have an agreement. Ratification of the UTU agreement means that 95% of the unionized rail workforce in the US has successfully concluded voluntary agreements.

The new agreement covers more than 30 railroads, including the Class 1 railroads Burlington Northern-Santa Fe, CSX, Kansas City Southern, Norfolk Southern and Union Pacific.