5-76. Operating forces can use rail and water modes to conduct troop movements, if they are available in an AO. Their use can provide flexibility by freeing other modes of transport for other missions. Their use normally involves a mixture of military and commercial assets, such as defense freight railway interchange railcars pulled by privately owned diesel-electric engines to transport tanks along railroad right-of-ways from one rail terminus to another. Responsibility for coordinating the use of railroads and waterways resides in the ARFOR headquarters in the theater of operations.