Although it is a bit expensive,(but, however) the transportation is very convenient.
The construction “虽然…, 但是 ….” can link two contradictory statements in Chinese. You can put the subject before or after “虽然” in the first clause, but “但是” is always placed at the beginning of the second clause. The second clause is the main clause that is opposite or stands in contrast to the first clause in meaning.
|(S) 虽然 (S) + first clause,||但是 + main clause|
|Although it is expensive,||(but) the transportation is convenient.|
|Although I really want to go,||(but) I don't have time.|