Time to resurrect an old thread.
Southeastern trains twitter says that a vehicle has hit the bridge again.
https://twitter.com/Se_Railway
NEW: (4/4) Replacement buses will conveying passengers between Dover Priory and Shepherds Well via Kearsney until further notice.
Southeastern ‏@Se_Railway 1h
NEW: (3/4) All stations between Shepherds Well and Dover Priory will not be served.
Southeastern ‏@Se_Railway 1h
NEW: (2/4) Train services between Dover Priory and London Victoria via Faversham may be terminated at short notice.
Southeastern ‏@Se_Railway 1h
NEW: (1/4) Owing to a vehicle striking a bridge between Kearsney and Dover Priory all lines are blocked.
This was an hour ago, so may be out of date.
Also, it doesn't actually say which bridge between Dover Priory and Kearsney.