。
The train glided out of the station.
Literal
Train [topic-は] slide-like-ように station [object-を] went-out.
ように ('like, as if') makes the verb 滑る ('to slide, glide') into an adverbial modifier for 出ていった. The full phrase 滑るように出ていく = 'to go out in a sliding manner.' The を on 駅 marks it as the departure point. 出ていった combines 出る (go out) + ていく (motion away from speaker), painting a picture of the train sliding smoothly away.