text: Sustainment
  Note. (See ATP 3-21.20, appendix H for a notional concept of support scenario, used for
  discussion purposes, of an IBCT during the conduct of offensive combat operations.)
  BATTALION AND SQUADRON ECHELONS
  9-148. As discussed earlier, an FSC from the BSB supports each battalion and squadron in the BCT. The
  FSC performs the logistics function within the battalion or squadron echelon of support, referred to as unit
  trains in one location, or echeloned trains within an area of operations. Unit trains at the battalion or squadron
  level are appropriate when the unit is consolidated in an assembly area, during reconstitution, major
  movements, or when terrain or distances restrict movement causing the unit to depend on aerial resupply and
  evacuation for support. The BCT normally operates in echeloned trains where subordinate unit trains employ
  into multiple locations.
  9-149. Echeloned trains at the battalion and squadron can be organized into combat trains and field trains.
  Battalion and squadron trains are used to array subordinate sustainment elements (unit personnel, vehicles,
  and equipment) including their designated FSC. The battalion or squadron commander and staff, the BSB
  commander and staff, and the FSC commander collaborate to determine the best method of employment
  commensurate with the BCT’s concept of support and commander’s guidance. Echeloning of support can
  include the battalion or squadron aid station, elements of the S-1 section and S-4 section, and elements of the
  FSC.
  Combat Trains
  9-150. Combat trains usually consist of elements of the battalion or squadron S-1 section, S-4 section, and
  aid station, the maintenance collection point and other selected elements of the FSC. The FSC typically
  positions its commander or first sergeant, field feeding section, portions of the distribution platoon,
  maintenance control officer, and portions ofthe maintenance platoon in the combat trains. The battalion and
  squadron commanders position key personnel, staff and subordinate company leaders, and assets in the trains
  based on the best location to support the mission. Commanders consider the mission variables of METT-TC
  when selecting the location for their combat trains.
  9-151. When established, the combat trains command post (graphically depicted as the CTCP) plans and
  coordinates sustainment operations in support of the tactical operations. The combat trains command post
  serves as the focal point for all administrative and logistical functions for the battalion or squadron. The
  combat trains command post may serve as an alternate CP for the battalion or squadron main CP. The
  battalion or squadron S-4 usually serves as the combat trains CP sustainment officer in charge and the
  maintenance control officer usually serves as the maintenance collection point officer in charge. The
  headquarters and headquarters company (battery or troop) commander usually exercises command and
  control for their respective combat trains CP. The combat trains CP serves the following functions:
  (cid:122) Tracks the current battle.
  (cid:122) Controls sustainment support to the current operation.
  (cid:122) Provides sustainment representation to the main CP for planning and integration.
  (cid:122) Monitors supply routes and controls the sustainment flow of materiel and personnel.
  (cid:122) Coordinates evacuation of casualties, equipment, and detainees.
  9-152. Units position the maintenance collection point where recovery vehicles have access, or where
  maintenance personnel perform major or difficult maintenance. The combat trains must be mobile enough to
  support frequent changes in location, time and terrain permitting, under the following conditions when—
  heavy use or traffic in the area may cause detection, area becomes worn by heavy use such as in wet and
  muddy conditions, or security is compromised.
  Field Trains
  9-153. Field trains are positioned based on METT-TC considerations and are often located in the BSA. The
  field trains include battalion or squadron sustainment assets not located with the combat trains. Field trains
  can provide direct coordination between the battalion or squadron and the BSB.