'Stand' radical on the left — itself a pictograph of a person standing on the ground (人 over 一). 站 inherits and intensifies that meaning: the original 'stand' verb. By natural extension a place where people stand still — a station, stop, post — 车站, 加油站. The radical on the left keeps the body-upright image present.
Right component supplies the sound, zhàn → zhàn, an exact match. 占 originally pictured a tortoise-shell crack being read in divination. Its other reading zhān shows up in 粘 (sticky), 沾 (moisten), but the zhàn rime carries through 站 cleanly.
