Le trajet vers le centre-ville est long quand le métro est en panne.

Trajet means journey, trip, or route in the sense of getting from one place to another.

In this sentence, Le trajet refers to the trip/getting there. It is a very natural word when talking about commuting or travel between places.

A useful distinction:

• trajet = the journey from point A to point B
• voyage = a trip in the broader sense, often longer or more significant, like a vacation or a trip abroad

So here, Le trajet vers le centre-ville is more natural than Le voyage vers le centre-ville, because this is about the commute or route to downtown, not a major trip.

Vers means toward or in the direction of.

So:

• vers le centre-ville = toward downtown / to downtown
• au centre-ville = in downtown / to downtown depending on context, but it focuses more on the destination itself than the movement toward it

In this sentence, vers emphasizes the journey in the direction of downtown:

• Le trajet vers le centre-ville = the trip toward downtown

You could sometimes hear le trajet jusqu’au centre-ville, which would mean the trip all the way to downtown and sounds a bit more explicitly destination-focused.

Because centre-ville is a fixed compound noun in French meaning city center or downtown.

French often joins certain compound nouns with a hyphen. So:

• le centre-ville = downtown
• en centre-ville = downtown / in the city center

This is just the standard spelling. It is something you mainly need to memorize as a vocabulary item.

Yes, long does agree — and here it agrees with trajet, which is masculine singular.

• le trajet = masculine singular
• so the adjective is long

If the noun were feminine, it would change:

• la journée est longue

If it were plural:

• les trajets sont longs
• les journées sont longues

So in your sentence:

• Le trajet ... est long is correct because trajet is masculine singular.

French uses articles much more often than English does.

So French usually says:

• Le trajet = the journey / the trip
• le métro = the metro / subway

Even when English might say something more general like Travel to downtown is long when metro is down, French normally keeps the article:

• Le trajet vers le centre-ville est long quand le métro est en panne.

This is very normal French. Leaving out the articles would sound ungrammatical.

En panne is a very common expression meaning:

• broken down
• out of order
• not working

It is especially used for machines, vehicles, appliances, and systems:

• La voiture est en panne. = The car has broken down.
• L’ascenseur est en panne. = The elevator is out of order.
• Le métro est en panne. = The subway/metro is not working.

Why not cassé?

• cassé usually means broken in the sense of physically damaged
• en panne means not functioning, which is exactly the idea here

So le métro est en panne means the metro system is not working, not necessarily that it is physically smashed.

Yes, quand means when, and it works perfectly here.

• quand = when
• lorsque = when, but usually a little more formal
• si = if, which changes the meaning

So:

• quand le métro est en panne = when the metro is down
• si le métro est en panne = if the metro is down

In this sentence, quand suggests a recurring situation: whenever the metro is down, the trip is long.

You could replace it with lorsque, but that would sound a bit more formal:

• Le trajet vers le centre-ville est long lorsque le métro est en panne.

French often uses the present tense to express:

• general truths
• habitual situations
• things that are regularly true

So this sentence means something like:

• The trip to downtown is long when the metro is down or
• Whenever the metro is down, the trip to downtown is long

It is not necessarily talking about only one specific moment. It can describe a general pattern.

English does this too:

• Traffic is bad when it rains.
• The trip is long when the metro is down.

Not in exactly the same way.

• Le trajet vers le centre-ville est long specifically names what is long: the trip to downtown
• C’est long means It’s long and is much less specific

You could say:

• Le trajet vers le centre-ville est long quand le métro est en panne. or more casually:
• C’est long d’aller au centre-ville quand le métro est en panne.

Both are possible, but they are structured differently:

• Le trajet ... est long = the journey is long
• C’est long de + infinitive = it is long / it takes a long time to do something

Here, le métro most naturally refers to the metro system in general, not one individual train.

So:

• le métro est en panne = the metro is down / the subway system is not working

In real life, context matters. Sometimes it could refer to a specific line or service disruption, but in a sentence like this, learners should understand it as the metro service in general.

This is common in French:

• Le téléphone ne marche pas. = The phone isn’t working.
• Le métro est en panne. = The metro is down.

A French speaker would understand it as a general statement:

• getting to downtown takes a long time when the metro is not working

The structure is:

• Le trajet vers le centre-ville = the trip toward downtown
• est long = is long / takes a long time
• quand le métro est en panne = when the metro is down

So the sentence sounds natural and everyday, especially in a context about commuting, transportation problems, or city life.