Learn Farsi: آیا خرابی خود دستگاه باعث افزایش سرفاصله شد؟ - Did the breakdown of the machine itself cause an increase in the headway?

In khod-e dastgah, the word khod acts as an emphatic identity modifier meaning "the machine itself." It is not a reflexive pronoun indicating the machine did something to itself. Notice that unlike English, the emphatic khod comes before the noun it emphasizes and connects to it with an ezafe.

How do the ezafe vowels work in the phrase kharabi khod dastgah?

You need two ezafe links to chain this together: kharabi-ye khod-e dastgah. The first ezafe (pronounced with a 'ye' sound because kharabi ends in a vowel) links "breakdown" to the noun phrase "the machine itself". The second ezafe connects the emphatic modifier khod to the noun dastgah.

Why do we use the verb shod (became) for "caused"?

To say "cause something" in Farsi, you typically use the compound structure ba'es-e [something] shodan (literally "to become the cause of [something]"). In this sentence, the breakdown "became the cause of" the increase (ba'es-e afzayesh ... shod).

What kind of distance is a sar-fasele?

While fasele just means "distance" or "gap," sar-fasele (literally "head-distance") is a specific technical term for "headway" or "interval." It is most commonly used in public transportation to describe the scheduled time or distance between consecutive trains or buses on a route.