Learn Hardcore French: Malheureusement, le métro est en panne ce matin. - Unfortunately, the subway is broken down this morning.

être en panne = is out of order/is down (state). Example: Le métro est en panne.
tomber en panne = to break down (event). Example: Le métro est tombé en panne ce matin.
Use these with machines, vehicles, and services, not with people.

Why is it le métro and not la métro or un métro?

métro is masculine in French, so it takes le.
The definite article le is used because we mean the known system/service, not just any subway.
You would use un métro only if you meant “a subway train” in a very specific context, which is rare; usually it’s the system, so le métro.

Can I move malheureusement or ce matin to other positions?

Yes. All are correct, with slight changes in emphasis:

Malheureusement, le métro est en panne ce matin. (neutral, sets the tone)
Le métro est malheureusement en panne ce matin. (focuses the adverb inside the statement)
Ce matin, le métro est en panne, malheureusement. (time first, regret at the end)
Time expressions like ce matin often go at the end, but fronting them is common.

How do I pronounce this naturally?

Malheureusement: the h is silent; eu sounds like the French rounded vowel (close to the vowel in French peur); final -ment is like a nasalized -ma(n).
le métro: é is a closed “ay” sound; stress tends to fall at the end of prosodic groups in French, not strongly on a single syllable.
est en: there’s a liaison; you’ll hear a linking t: est‿en.
en panne: en is nasal; panne has a pronounced n (not nasal) because of the double n.
Overall rhythm: link words smoothly and avoid stressing each word separately.

Why is there a comma after Malheureusement?

Because it’s a sentence adverb set off at the start. French commonly places a comma after initial adverbs or adverbial phrases to mark a pause and set the tone.

What does the accent in métro do?

The acute accent on é forces a closed, clear vowel, roughly like the “ay” in English say, but shorter and tenser.
Without é, the pronunciation of e would be ambiguous or different; the accent tells you exactly how to say it.

Does en panne change with number or gender?

No. It’s a fixed prepositional expression. Examples:

Le métro est en panne.
Les métros sont en panne. It stays en panne in all cases; you don’t write en pannes.

What’s the difference between ce matin, le matin, and dans la matinée?

ce matin = this morning (today’s morning).
le matin = in the morning(s) / mornings in general, or the morning as a general time.
dans la matinée = sometime during the morning (less precise, spans the whole morning period).

Can I say aujourd’hui matin for “this morning”?

Generally no. Say ce matin. French avoids aujourd’hui matin in standard usage; ce matin already means “this morning (today).”

Is en here the pronoun en?

No. In en panne, en is a preposition meaning “in/into a state of.” The whole thing is an idiomatic set phrase meaning “broken down/out of order.”

How do I negate this or turn it into a question?

Negation: Le métro n’est pas en panne ce matin. (note the n’ before est)
Neutral question: Est-ce que le métro est en panne ce matin ?
Inversion (more formal): Le métro est-il en panne ce matin ?

Could I say Le métro ne marche pas ce matin or Le métro est hors service?

Yes:

ne marche pas / ne fonctionne pas = not working (everyday, informal to neutral).
hors service = out of service (notice, technical, or formal tone). All are acceptable; en panne is very common and idiomatic.

When is métro capitalized?

As a common noun, it’s lowercase: le métro.
Capitalize at the start of a sentence or when part of a proper name or title. Specific lines are usually written la ligne 1, la ligne 4, etc., still lowercase for ligne.

Why est and not es or sont?

Because le métro is third person singular:

je suis, tu es, il/elle est, nous sommes, vous êtes, ils/elles sont. Here it matches il/elle est → est.

Could I replace Malheureusement with Hélas or C’est dommage?

Hélas, le métro est en panne ce matin. works but sounds a bit literary or dramatic.
C’est dommage, le métro est en panne ce matin. is natural and conversational.
Malheureusement is neutral and very common in speech and writing.

Is Le métro est en panne ce matin how people would actually say it? Any more idiomatic options?

It’s fine and clear. In real-life transport updates, you’ll also see/hear:

Trafic interrompu sur la ligne X ce matin.
Il y a une panne sur la ligne X.
Plusieurs lignes de métro sont en panne.
Informally: Ça ne marche pas ce matin, Le métro est à l’arrêt.