Translation:We will arrive by train early in the morning tomorrow.
Here is a god example of how mistakes happen in this DUO course (there are, elas, many of the kind). The word... tog... (train) shall be pronounced like... tåg (in Danish). But DUO uses the word... tog (past tense of the word to take, at tage) instead. Thus, the same written word, but with different meanings, and different pronunciations.