This manual describes the organizations, processes, procedures, and systems involved in the rail operations across the military spectrum. The focus of this manual is for the reader to gain an understanding of the Army rail system and how it functions. Rail transport operations in developed nations are considered to be a HN provided service. In contingency areas, US rail units may have to be employed to support the theater of operations. This FM sets forth transportation rail doctrine and organizational structure. It is written to explain the functions of rail transport operations service in a theater of operations. It provides basic information for commanders and staffs of supporting units and for staff officers of higher HQ. It is also intended to serve as a text for student instruction and training of rail unit personnel. This manual remains consistent with Army operations, logistics doctrine, and concepts currently published or in the process of being published. However, the reader is cautioned that logistics doctrine is changing - and changing rapidly. The on-going efforts to reduce the Army logistics footprint and move to the Objective Force will require doctrinal change. Users acting within the scope of their authority may vary from this doctrine in this manual when such variation will result in improved operations. The Army's environmental strategy into the 21st century defines its philosophy and commitment in protecting and preserving the environment and natural resources for present and future generations. Sound environmental practices and considerations must be integrated into all Army documents, missions, and operations. In keeping with the Army's vision to be a national leader in environmental stewardship, commanders and leaders must ensure that all local, state, federal, and host nation laws and regulations pertaining to the environment are included in the planning process and followed to an extent consistent with operational considerations.