فاتني القطار، فسألت موظف المحطة.

Because the verb فات is commonly used in Arabic in the sense of to pass someone by, to escape someone, or to be missed by someone.

So فاتني القطار is literally something like:

• فات = missed/passed by
• ني = me
• القطار = the train

So the structure is closer to The train missed me or The train passed me by, even though the natural English translation is I missed the train.

This is a very normal Arabic way to express missing a train, bus, opportunity, class, and so on.

-ني is the attached pronoun meaning me.

So:

• فات = missed / passed by
• فاتني = missed me / passed me by

This pronoun attaches directly to the verb. In this sentence, it refers to the speaker.

Because the subject is القطار, and القطار is a masculine noun in Arabic.

So the verb matches it in gender:

• فاتني القطار = The train missed me
• but فاتتني الحافلة = The bus missed me, because الحافلة is feminine

So the choice between فات and فاتت depends on the gender of the noun doing the action.

Because Arabic often uses a verb-first sentence pattern, especially in Modern Standard Arabic.

So here the order is:

• فاتني = the verb plus attached pronoun
• القطار = the subject

This kind of order is very common in Arabic verbal sentences.

You could also say القطار فاتني, but that puts more focus on the train. The version in your sentence is the more neutral verbal style.

The فـ means so, then, or and so. It connects the two actions and shows that the second happened as a result of the first.

So:

• فاتني القطار = I missed the train
• فسألت موظف المحطة = so I asked the station employee

It is a very common connector in Arabic and often shows sequence or consequence.

It is built into the verb itself.

سألت means I asked, and the ending -ت shows the subject I in the past tense.

So Arabic does not need a separate أنا here. You can say أنا سألت for emphasis, but normally just سألت is enough.

Because this is an iḍāfa structure, often called a construct phrase.

موظف المحطة means the employee of the station, which in natural English becomes the station employee.

In an iḍāfa:

• the first noun usually does not take الـ
• the second noun can be definite
• the whole phrase becomes definite because the second noun is definite

So:

• موظف = employee
• المحطة = the station
• موظف المحطة = the station employee

You do not say الموظف المحطة here.

Because the verb سأل takes the person asked as a direct object.

So:

• سألتُ موظفَ المحطة = I asked the station employee

No preposition is needed before the person.

If you want to mention the topic you asked about, you often use عن:

• سألتُ موظفَ المحطة عن موعد القطار = I asked the station employee about the train time

So the pattern is often:

• سأل + person
• optionally عن + topic

With full vowels, it would normally be:

فاتني القطارُ، فسألتُ موظفَ المحطةِ.

A careful pronunciation would be approximately:

fātanī al-qiṭāru, fa-sa'altu muwaẓẓafa al-maḥaṭṭati

A few useful notes:

• القطارُ ends in -u because it is the subject
• سألتُ ends in -tu because it means I asked
• موظفَ ends in -a because it is the direct object
• المحطةِ ends in -i because it is the second noun in the iḍāfa

In normal writing, these short vowels are usually omitted, so you most often see:

فاتني القطار، فسألت موظف المحطة.

It is very common, and it is used for many things that someone fails to catch, attend, or take advantage of.

For example:

• فاتني الدرس = I missed the lesson
• فاتتني الفرصة = I missed the opportunity
• فاتني الموعد = I missed the appointment

So learning فاتني / فاتتني is very useful, because it appears in many everyday situations.