From National Rail website:
Rail replacement bus services calling at all stations between New Cross Gate and West Croydon except Penge West but additionally at Crystal Palace and Selhurst are scheduled to operate as follows:
SATURDAY
From Forest Hill towards New Cross Gate
Every 15 minutes at 00, 15, 30 and 45 past from 0530 to 0015 (5 minutes later from Honor Oak Park)
From Forest Hill towards West Croydon every 15 minutes at 13, 28, 43 and 58 past from 0543 to 2358 then 0001, 0014, 0023, 0028, 0033, 0043, 0053, and 0103 (5 minutes earlier from Honor Oak Park)
From New Cross Gate towards Forest Hill every 15 minutes from 0530 to 2345 then 0001, 0010, 0015, 0020, 0030, 0040, and 0050
SUNDAY
From Forest Hill towards New Cross Gate
Every 15 minutes from 0630 to 0015 (5 minutes later from Honor Oak Park)
From Forest Hill towards West Croydon every 15 minutes at 13, 28, 44 and 58 past from 0713 to 0013 (5 minutes earlier from Honor Oak Park)
From New Cross Gate towards Forest Hill every 15 minutes at 00, 15, 30 and 45 from 0700 to 2345 then 0001
BUS STOPS FOR REPLACEMENT BUS SERVICES
For stations towards New Cross Gate the buses will use Bus Stop E on Dartmouth Road (by Stanford Estates where 122 stops) and bus stop HB on Honor Oak Park
For stations towards West Croydon the buses will use bus stop B in London Road (by the Guava Kitchen) and bus stop HA on Honor Oak Park
From New Cross Gate the buses will use bus stop R in New Cross Road
ALTERNATIVE RAIL OPTIONS
Catford Bridge
To London Bridge - 4 per hour on Saturday / 2 per hour on Sunday
To Cannon Street - 2 per hour Saturday & Sunday
To Waterloo East and Charing Cross - 2 per hour Saturday / none on Sunday
Catford, Crofton Park and Nunhead
To Elephant & Castle and Blackfriars (2 per hour on Saturday but none on Sunday
Crystal Palace
To London Bridge via Tulse Hill 2 per hour Saturday & Sunday but takes 28 minutes on Saturday and up to 34 minutes on Sunday!
Peckham Rye
To London Bridge 4 per hour Saturday & Sunday
To Elephant & Castle and Blackfriars 2 per hour on Saturday but no direct on Sunday (change at London Bridge
Penge East and Sydenham Hill
To Brixton and Victoria 2 per hour Saturday & Sunday