Togselskapet vurderer erstatningsbeløpet etter reisegarantien.

Because Norwegian normally writes noun compounds as one word.

• togselskapet = tog
  • selskap
    • -et
• erstatningsbeløpet = erstatning
  • -s-
    • beløp
      • -et

The last part is the main noun, and the earlier part(s) describe it. So togselskap is a kind of selskap and erstatningsbeløp is a kind of beløp.

That -s- is a linking element used in many Norwegian compounds. It does not usually mean possession here.

So erstatningsbeløp is not literally compensation's amount in the English possessive sense; it is just the normal compound form meaning compensation amount. Some compounds use this linking -s-, and some do not.

Those are definite singular endings, and the choice depends on the noun’s gender.

• selskap is neuter → selskapet
• beløp is neuter → beløpet
• garanti is usually common gender in Bokmål → garantien

In compounds, the last element decides the gender and the ending. So togselskapet is neuter because selskap is neuter.

Vurderer is the present tense of å vurdere.

It can mean things like:

• assesses
• evaluates
• considers

In this sentence, it most naturally means something like assesses or determines.

Not in the time sense. Here etter means according to, under, or in accordance with.

So etter reisegarantien means something like:

• according to the travel guarantee
• under the travel guarantee

This is a very common use of etter with rules, laws, agreements, and policies.

Because Norwegian often shows definiteness by adding it to the end of the noun.

• selskapet = the company
• beløpet = the amount
• garantien = the guarantee

A separate definite word is usually added when there is an adjective or similar modifier, for example det store selskapet.

The sentence follows normal Norwegian main-clause word order:

Togselskapet + vurderer + erstatningsbeløpet + etter reisegarantien

So it is:

• subject: Togselskapet
• verb: vurderer
• object: erstatningsbeløpet
• prepositional phrase: etter reisegarantien

This is a straightforward example of standard main-clause structure.

It means the amount of compensation, not just compensation in a general sense.

Compare:

• erstatning = compensation
• erstatningsbeløp = compensation amount / amount of compensation

So the sentence is talking specifically about the sum to be paid.

Yes. It is:

• reise = travel
• garanti = guarantee
• -en = definite singular ending

So reisegarantien is the travel guarantee. As with other compounds, the last part—garanti—is the main noun and determines the grammatical ending.