Så vidt togselskapet kan se, er billettkvitteringen nok for refusjonskravet.

Yes, så vidt often means barely in other contexts, but not here.

In this sentence, så vidt ... kan se is an idiomatic expression meaning:

• as far as ... can see
• as far as ... can tell
• from what ... can tell

So:

• Så vidt togselskapet kan se = As far as the train company can see / tell

This is a very common source of confusion because så vidt has more than one meaning in Norwegian.

Because Norwegian usually forms compound nouns as one word.

So:

• tog = train
• selskap = company
• togselskap = train company

This is very normal in Norwegian. English often writes these as two words, but Norwegian typically joins them into one compound.

Here, togselskapet is the definite form:

• et togselskap = a train company
• togselskapet = the train company

Because kan se here means something like can tell, is able to determine, or judging from what it has.

So the sentence is not really about physical sight. It means:

• As far as the train company can tell
• From what the train company can determine

If you used ser instead, it would sound more literal and usually less idiomatic in this expression.

The pattern så vidt noen kan se is very common.

This is because Norwegian follows the V2 rule in main clauses: the finite verb normally comes in the second position.

The sentence starts with the fronted expression:

• Så vidt togselskapet kan se

After that, the finite verb must come next:

• er

So the structure is:

• Så vidt togselskapet kan se, er billettkvitteringen nok for refusjonskravet.

If there were no fronted phrase, the normal order would be:

• Billettkvitteringen er nok for refusjonskravet.

So this is a standard Norwegian word-order change caused by putting something first.

It is a compound noun in the definite singular:

• billett = ticket
• kvittering = receipt
• billettkvittering = ticket receipt
• billettkvitteringen = the ticket receipt

In context, it means the receipt or proof of purchase for the ticket.

A learner might also wonder why it is not kvitteringen for billetten. That version is possible too, but billettkvitteringen is a compact compound form, which is very natural in Norwegian.

Because the definite article in Norwegian is often added to the end of the noun, instead of being a separate word.

So:

• et refusjonskrav = a refund claim
• refusjonskravet = the refund claim

This is the normal Norwegian definite form.

The same thing happens in:

• togselskapet = the train company
• billettkvitteringen = the ticket receipt

Here nok means enough or sufficient.

So:

• billettkvitteringen er nok = the ticket receipt is enough / sufficient

Be careful: nok can also mean probably in other sentences. For example:

• Det er nok sant. = That is probably true.

But in your sentence, nok clearly means sufficient.

Here for means something like:

• for the purpose of
• for
• in relation to

So:

• nok for refusjonskravet = enough for the refund claim

In other words, the ticket receipt is sufficient documentation for making or supporting the refund claim.

This use of for is natural when talking about whether something is enough for an application, request, claim, process, and so on.

It is a formal compound noun:

• refusjon = refund / reimbursement
• krav = claim / demand / request
• refusjonskrav = refund claim
• refusjonskravet = the refund claim

It is understandable and correct, especially in formal or administrative language.

Depending on context, Norwegian might also use other expressions such as:

• krav om refusjon
• søknad om refusjon

But refusjonskrav is perfectly plausible and fits a formal customer-service style.

It contains a clause-like structure, but in this sentence it functions as a fronted expression meaning as far as the train company can tell.

The important thing for a learner is this:

• it comes first as a kind of comment frame
• then the main clause follows
• because something else is first, the verb in the main clause moves before the subject: er billettkvitteringen

So even if you do not analyze it deeply, the practical lesson is: when a phrase like this is placed first, Norwegian main-clause word order still follows the V2 rule.

Yes. That is a very natural translation.

A few natural English renderings are:

• As far as the train company can tell, the ticket receipt is enough for the refund claim.
• As far as the train company can see, the ticket receipt is sufficient for the refund claim.
• From what the train company can tell, the ticket receipt should be sufficient for the refund claim.

The Norwegian sentence is slightly formal, and English would often also sound best with slightly formal wording such as sufficient or refund claim.

Yes, it is understandable and broadly natural, especially in a formal or customer-service context.

That said, depending on style, a Norwegian speaker might also say something like:

• Så vidt togselskapet kan se, er billettkvitteringen tilstrekkelig for refusjonskravet.
• Så vidt togselskapet kan se, er billettkvitteringen nok til å fremme refusjonskravet.
• Så vidt togselskapet kan se, er billettkvitteringen tilstrekkelig dokumentasjon for refusjonskravet.

Your original sentence is fine, but tilstrekkelig may sound a bit more formal and precise than nok in official writing.

A simpler version without the fronted expression would be:

• Billettkvitteringen er nok for refusjonskravet.

That is the core statement:

• subject: billettkvitteringen
• verb: er
• complement: nok
• prepositional phrase: for refusjonskravet

Then the original sentence adds the extra frame:

• Så vidt togselskapet kan se, ...

This is useful to soften the statement and show that it is based on the company’s current judgment, not an absolute guarantee.