Ground elements that have an experience level lower than their unit’s morale will increase their
experience at least one point per turn, but have a chance to gain up to a total of five experience points. The normal experience gain is two to three points per turn. Ground elements in units in good supply, especially if they are located on a railhead (20.1.1) will be able to gain more experience during training, as will ground elements that participated in combat the previous turn.
20.1.1
The
last friendly controlled undamaged rail line hexes at the end of these paths is considered a supply source and designated a rail head.
Is the best experience gain on a railhead or just a friendly rail hex?