"Ваш вагон номер тринадцять."

Translation: Your carriage is number thirteen.

[ElizabethC303587]

could "Your train car number is 13" be accepted?

[deactivated user]

No, you've made "train car" a modifier to "number". In Ukrainian, that would be «Ваш номер вагону — тринадцять». That is also correct, but it has a different grammar.

[sagitta145]

That would be "Номер вашого вагону — тринадцять"

[Wayne948533]

Why can't "Your carriage number is thirteen" be accepted?

[sagitta145]

It's accepted now, allowing for flexibility of phrasing. Mind, however, that grammatically these sentences are not identical.

Your carriage is number 13 - Ваш вагон номер тринадцять (subject - "вагон")

Your carriage number is 13 - Номер вашого вагону — тринадцять (subject - "номер")