عامل النقل ينقل الحمولة عبر الممر.

Because عامل النقل is an iḍāfa construction, often called a "noun + noun" or "of" construction.

• عامل = worker
• النقل = transport

Together, عامل النقل means transport worker or literally worker of transport.

In an iḍāfa:

• the first noun usually does not take ال
• the second noun can be definite, and if it is definite, the whole phrase becomes definite

So:

• عامل نقل = a transport worker
• عامل النقل = the transport worker / the worker of the transport sector

That is why عامل does not have الـ here.

Here, عامل is a noun meaning worker.

It originally comes from the root related to work (ع-م-ل), and structurally it is an active participle. In Arabic, active participles often become ordinary nouns in real usage.

So although عامل is historically a participle, in this sentence you should understand it simply as:

• عامل = worker

Be careful not to confuse it with other meanings of عامل, which can sometimes mean things like factor in math or science contexts.

ينقل is the imperfect (non-past/present) form of the verb نقل.

• نقل = to transport, move, carry, transfer
• ينقل = he transports / he is transporting / he transports regularly

In MSA, the imperfect can express:

• a present action
• a habitual action
• sometimes a near-future action, depending on context

So ينقل here can mean something like:

• he transports
• he is transporting

Its root is ن-ق-ل, which often has the general idea of moving or transferring something.

Arabic allows more than one normal word order.

This sentence uses:

• Subject + Verb + Object
• عامل النقل ينقل الحمولة

But Arabic also commonly allows:

• Verb + Subject + Object
• ينقل عاملُ النقل الحمولةَ

Both are grammatical in MSA.

Very generally:

• Verb-first order is often felt to be more neutral or more classically typical
• Subject-first order can put more focus or emphasis on the subject

So starting with عامل النقل is completely normal.

Because it has الـ, so it means the load / the cargo / the payload, not just a load.

• حمولة = a load / cargo
• الحمولة = the load / the cargo

Arabic uses definiteness a lot more explicitly than English. If the sentence is talking about a specific known load, الحمولة is natural.

Also, حمولة is a common noun for a load, cargo, or payload, especially in transport or logistics contexts.

Because حمولة is a grammatically feminine noun.

A very common sign of feminine nouns in Arabic is the ending:

• ـة / ة (tāʾ marbūṭa)

So حمولة is feminine by form.

In this sentence, that does not cause a very visible change, because الحمولة is the object, not the subject. But if you referred back to it with a pronoun or adjective, the feminine gender would matter.

For example, an adjective describing it would normally be feminine too.

عبر means something like:

• through
• across
• via

In this sentence, it introduces الممر and shows the path or route of the movement.

So:

• عبر الممر = through the corridor / across the passageway

In MSA, عبر is very common in formal writing and speech. Depending on context, English may translate it in different ways, but the basic idea is movement through or across a space.

الممر means the corridor, the passage, or the passageway.

It is definite because it has الـ, so the sentence is talking about a specific corridor or passage.

After عبر, the noun is commonly treated as part of a fixed formal expression meaning through/across X:

• عبر الطريق
• عبر الجسر
• عبر الممر

So عبر الممر is a very natural MSA phrase.

Yes. In fully vowelled formal Arabic, the sentence would show case endings. It would look approximately like this:

عامِلُ النَّقلِ يَنقُلُ الحَمولةَ عَبرَ المَمَرِّ

The important roles are:

• عامِلُ → nominative, because it is the subject
• النقلِ → genitive, because it is the second term of the iḍāfa
• الحمولةَ → accusative, because it is the direct object
• الممرِّ → genitive after عبر in this construction

In normal everyday Arabic writing, these short vowel endings are usually omitted, so learners have to infer the grammar from structure.

Sometimes yes, but the meaning changes slightly.

• ناقل = carrier / transporter / one who transports
• عامل النقل = transport worker / transportation worker

So:

• ناقل focuses more on the role of carrying/transporting
• عامل النقل focuses more on the person as a worker in the transport field

If you are describing someone's job in a general or institutional way, عامل النقل is often more natural. If you want a more direct "carrier/transporter" idea, ناقل may work.

A useful breakdown is:

• عامل النقل = the transport worker
• ينقل = transports / is transporting
• الحمولة = the load / cargo
• عبر الممر = through the corridor / across the passageway

So grammatically, it is:

• subject
• verb
• direct object
• prepositional/adverbial phrase of route

This is a very good example of a basic MSA sentence with:

• an iḍāfa phrase
• an imperfect verb
• a direct object
• a path expression with عبر