After three and a half years of disruption, the Thameslink route is back to normal from this Saturday. The full timetable is here: http://www.firstcapitalconnect.co.uk/static/timetables/timetable/FC1205_TL_BOOK.pdf (page 106 onwards).
Points worth noting:
* The last train from Blackfriars to Herne Hill will be at 23:46, 90 minutes later than the current last train.
* Trains run from Blackfriars every 15 minutes until 21:16 and then every 30 minutes until 23:46.
* Going north, trains run every 15 minutes until 21:57 and then every 30 minutes until 23:27. The 21:57 and all later trains run all stops to Bedford; earlier trains alternate between St. Albans and Luton.
* The first northbound train on Saturday is at 06:01.
* Trains run from Blackfriars every 15 minutes until 20:45. The last train to Herne Hill is at 21:15.
* Northbound trains run every 15 minutes until 21:57, with a final train at 22:27.
* Every second northbound train during the day and the last two northbound trains (21:57 and 22:27) terminate at Blackfriars, but passengers can change on to trains from London Bridge to travel further north.
* The first northbound train is at 10:14.
This timetable won't be fully implemented until Sunday 27 May (weekend evening services will run every 30 minutes instead of every 15 until then), but all of the last train times are valid from Saturday. And finally:
Trains will run between Bedford and Three Bridges (calling at Luton and Gatwick airports) throughout the night. The only stations in central London served by these trains will be St. Pancras and Blackfriars, so anyone in Herne Hill will need to get to Blackfriars to use them. The N68 calls at Lancaster Place near Temple, less than 10 minutes walk away.
London Bridge will not have any overnight trains until its rebuilding is complete in 2018, so don't go there if you have a horribly early flight at either airport.