text: Movement to Contact
  deployment of the main body as long as possible. Commanders may instruct the advance guard to eliminate
  small pockets of resistance bypassed by the covering force (if both are used). The conduct of the security
  forces in the movement to contact are the same as those for security operations. (See Chapter 13 for additional
  information on security operations.)
  MAIN BODY
  4-9. A main body consists of forces not assigned to security duties. It normally includes the maneuver
  forces conducting the main effort once contact is made with the enemy as well as fires, engineer, and
  sustainment assets to support the operation The combat elements of the main body prepare to respond to
  enemy contact that the unit’s security forces make. If the situation allows, commanders can assign a follow
  and support mission to a subordinate maneuver unit. This allows that subordinate unit to relieve security
  forces and perform tasks such as containing bypassed enemy forces, handling dislocated civilians, and
  clearing routes. Security forces can then continue their primary mission.
  4-10. Units frequently find that their main supply routes (MSRs) become extended as operations proceed.
  Aerial resupply may be necessary to support large-scale movement to contacts or to maintain the momentum
  of the main body. Combat trains containing fuel, ammunition, medical assets, and maintenance assets move
  with their supported battalion or company team. Fuel and ammunition stocks remain loaded on tactical
  vehicles in the combat trains so they can quickly move when necessary. Battalion field trains move with a
  higher support echelon, such as the brigade support battalion, in the main body of each BCT. Aviation units
  use forward arming and refuel points (known as FARPs) to reduce aircraft turnaround time.
  RESERVE
  4-11. Commanders designate a portion of the main body for use as the reserve. The mission variables
  determine the size of the reserve, and the more unknown the enemy situation, the larger the size of the reserve.
  On contact with enemy forces, a reserve provides flexibility to react to unforeseen circumstances and allows
  a unit to resume its movement. See paragraphs 1-94 through 1-100 for more information on the reserve.
  COMMON CONTROL MEASURES FOR A MOVEMENT TO
  CONTACT
  4-12. Units use the minimal number and type of control measures possible in a movement to contact because
  of the uncertain enemy situation. These measures include designation of an assigned area with left, right,
  front, and rear boundaries, or a separate assigned area bounded by a continuous boundary in noncontiguous
  operations. Commanders further divide their assigned area into subordinate unit assigned areas to facilitate
  subordinate unit actions.
  4-13. A movement to contact usually starts from a LD at the time specified in the operation order.
  Commanders control a movement to contact by using phase lines, contact points, and checkpoints as required.
  They also control the depth of the movement to contact by using a LOA or a forward boundary. Figure 4-2
  on page 4-4 depicts example common movement to contact control measures and also depicts a limit of
  advance and not a forward boundary. Commanders can designate one or more objectives to limit the extent
  of a movement to contact and orient the force. However, these are often terrain oriented and used only to
  guide movement. Although a movement to contact may result in taking a terrain objective, the primary focus
  should be on gaining contact with enemy forces and developing the situation. If a unit has enough information
  to locate significant enemy forces, then it should plan an attack.
  4-14. Commanders use boundaries to separate the various organizational elements and clearly establish
  responsibilities between different organizations. They synchronize the movement to contact with control
  measures, battle drills, and formation discipline.