Learn Hardcore German: Die letzte U-Bahn fährt um neun Uhr. - The last subway leaves at nine o'clock.

In German all nouns are capitalized. U-Bahn is a shortened form of Untergrundbahn: the letter U stands for Untergrund, and Bahn remains the noun. A hyphen marks the abbreviation.

Why does the sentence use die letzte U-Bahn instead of eine letzte U-Bahn?

We use the definite article die because we refer to the last train of the day, a known specific one. Also, U-Bahn is feminine (like any noun ending in -bahn), so it takes die in the nominative.

Why does letzte end with -e and not -er or another ending?

Because it’s an attributive adjective following a definite article in the nominative feminine. After die, weak adjective endings apply: nominative feminine adjectives take -e, so letzte.

Why is the verb fährt placed in second position in the sentence?

German main clauses follow the verb‑second (V2) rule: the finite verb must occupy the second position, regardless of which element comes first.

Why do we use fahren for the subway here, rather than gehen?

In German, vehicles (trains, buses, cars, etc.) fahren. Gehen is used for walking or personal movement, not for trains departing.

Why is um used before neun Uhr to express the time?

For exact clock times, German uses um + accusative. So um neun Uhr means at nine o’clock.

Why is there no article before neun Uhr (for example, um die neun Uhr)?

Time expressions with um don’t take an article; you simply state the hour or minutes directly.

Could I start the sentence with um neun Uhr, and what happens to the word order?

Yes. You can front the time adverbial: Um neun Uhr fährt die letzte U-Bahn. The verb stays in second position, so the subject follows.

Can I use the separable verb abfahren instead of fahren here?

Yes. Using abfahren (to depart) is perfectly natural: Die letzte U-Bahn fährt um neun Uhr ab. In main clauses the prefix ab‑ moves to the end.