Learn Icelandic: Hraðlestin er farin frá pallinum. - The express train is gone from the platform.

This highlights the resultative aspect, which is common with verbs of motion like fara. Using vera (to be) plus the past participle describes the current state or result: the train is currently gone. If you used hafa plus the supine (Hraðlestin hefur farið), it would focus on the action itself, meaning "The express train has departed."

Why is the participle farin instead of the default form farið?

When you use vera with a verb of motion to show a resulting state, the past participle behaves like an adjective. That means it must agree in gender and number with the subject of the sentence. Because hraðlestin is a feminine singular noun, the participle takes the feminine singular nominative form, which is farin.

How do we know the gender of hraðlestin?

Hraðlest is a compound word made of hraður (fast) and lest (train). In Icelandic, compound words always take the gender of the final word. Since lest is a feminine noun, the entire compound is feminine, which is why it takes the feminine definite article -in.

Why does the word for platform end in -num in pallinum?