Extracted from Southeastern's website.
Saturday 16 January
Engineering work between Margate and Ramsgate
There are no train services calling at Broadstairs, Dumpton Park or Ramsgate. However, there are connecting replacement bus services, caling at these stations, operating in each direction between Margate and Ramsgate, and Ramsgate and Minster.
This engineering work may also affect train journeys to or from the following stations (in alphabetical order):
Ashford International, Bromley South, Canterbury West, Chatham, Chartham, Chilham, Chestfield & Swalecliffe, Ebbsfleet International, Faversham, Gillingham (Kent), Headcorn, Hildenborough, London Bridge, London Cannon Street, London Victoria, London Waterloo East, Longfield, Marden, Meopham, Newington, Orpington, Paddock Wood, Pluckley, Rainham (Kent), Rochester, Sevenoaks, Sittingbourne, Staplehurst, St Pancras International, Stratford International, Sturry, Teynham, Tonbridge, Whitstable or Wye
However I just typed into the journey planner From: STP to AFK for 16/01/10 @ 0900 and it gives me departures at 0842, 0912, 0940, 1012, 1042; So it appears that they are running to Ashford.