1. What time does the train arrive in Los Angeles?

2. What time does the train arrive at Los Angeles?
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Which preposition do we have to use? Are both okay?

In that question, "in" is used.

If you rephrase a bit -- ... train arrive at the Los Angeles station?

Thank you for your help. Can we use as follows?

The train arrives at New York, and then it will leave New York. The train will arrive at Washington D.C. at 11. It will leave the city in 10 minutes.

The train arrives in New York, and then it will leave New York. The train will arrive in Washington, D.C., at 11. It will leave the city in 10 minutes.

Notice the changes I made, including some punctuation!

Thank you for your help.

You're welcome!

Both prepositions, "in" and "at," can be used in these sentences, but they convey slightly different meanings.

1. "What time does the train arrive in Los Angeles?" - In this sentence, "in" is used to indicate arrival within the city of Los Angeles. It implies that the train will be arriving at a train station within the boundaries of the city.

2. "What time does the train arrive at Los Angeles?" - In this sentence, "at" is used to indicate arrival at the destination of Los Angeles. It implies that the train will be arriving at a specific location or terminal associated with Los Angeles.

So, the choice between "in" and "at" depends on whether you want to emphasize the train arriving within the city or at the destination itself. Both prepositions are grammatically correct, but the choice should be based on the intended meaning.