Combat engineers can cause a one column shift to the right on an attack, and one column shift to the left on a defense.
NATO combat engineers can support up to three, and PACT two, attacks or defenses or special missions (fortify, minefield emplacement, bridging, obstaclesetc, as outlined below), at half their movement allowance distance from the counter location, per turn, to the target hex.
The combat engineers must be stationary and not have moved, with the counter becoming a way to note the location of the battalion headquarters. The combat engineer modification to the column shift can be cancelled out by enemy combat engineers participating.
In the time-honored tradition, they can get sucked into their own battles, by being attacked, and are not available to support another unit.When the unit has had sub-elements deployed on remote missions (ieup to half the movement allowance distance) it defends at half-strength.
Combat engineers can emplace minefields, improve/fortify positions, clear obstacles, clear minefields, demolish bridges (one or more turns stationary & no other uses), and bridge rivers (various turns to complete missions, see below)