Breakdown of Vi träffades av en slump på tåget.
på
on / at / for (wait for) / in (believe in)
tåget
the train
träffas
to meet each other
av en slump
by chance
Questions & Answers about Vi träffades av en slump på tåget.
Why is there an -s at the end of träffades? Can I just say vi träffade?
The -s makes it a reciprocal verb, meaning the action happens to each other. If you just said vi träffade, it would mean 'we met [someone else]' and would sound incomplete here without a direct object. Vi träffades specifically means 'we met [each other]'.
Does slump mean the same thing as the English word 'slump'?
No, this is a false friend! In Swedish, en slump means a coincidence, fluke, or random chance. The fixed phrase av en slump is the standard way to say 'by chance' or 'by coincidence'.
Why do we use på instead of i for the train?
Just like in English, Swedish uses på (on) for large modes of public transport where you can stand up and walk around, such as a train (på tåget), bus (på bussen), or boat (på båten). You only use i (in) for smaller, enclosed vehicles like a car (i bilen).
If I wanted to emphasize 'by chance' and put av en slump at the beginning, how would the sentence change?
You would need to swap the subject and the verb to follow the V2 rule, which requires the verb to be the second grammatical building block in a main clause. The sentence would become: Av en slump träffades vi på tåget.