。
The train just left.
Literal
Train [topic-は] left [place-where-just-ところ] [copula-だ].
出たところだ is the ~たところだ pattern — 'just (now) did X.' ところ ('place, spot') is used here abstractly as 'the point in time,' and the tense of the preceding verb sets the temporal position. With ~た it means 'just now did'; with the dictionary form it means 'about to.'