Most Tube station ticket machines are only accepting bank cards. You can top up using your contactless and Oyster account, the TfL Oyster and contactless app or an Oyster ticket stop. Ticket machines at all London Overground and DLR stations are still accepting cash.
Affected Stops:
London, Fairlop
London, Farringdon
London, Finchley Road Station
London, Finchley Central
London, Finsbury Park
London, Fulham Broadway Station
London, Gants Hill
London, Gloucester Road
London, Golders Green
London, Goldhawk Road
London, Goodge Street Station
Grange Hill, Grange Hill
London, Great Portland Street
London, Greenford
London, Green Park
London, Gunnersbury Station
London, Hainault
London, Hammersmith (District and Piccadilly) Station
London, Hammersmith (H&C and Circle Lines)
London, West Hampstead Underground Station
London, Hampstead Station
London, Hanger Lane Station
London, Harlesden Station
London, Harrow & Wealdstone Station
London, South Harrow
London, North Harrow
London, Harrow-on-the-Hill
London, West Harrow Station
London, Hatton Cross
London, Heathrow Terminal 4
London, Heathrow Terminal 5
London, Heathrow Terminals 2 & 3 Underground Station
London, Hendon Central
London, High Barnet
London, Highbury & Islington Station
London, Highgate
London, Hillingdon Station
London, Holborn Station
London, Holland Park
London, Holloway Road Station
London, Hornchurch
London, Hounslow West
London, Hounslow East
London, Hounslow Central Station
London, Hyde Park Corner
London, Ickenham
London, Kennington Station
London, Kensal Green Station
London, Kensington (Olympia) Station
London, High Street Kensington
London, Kentish Town
London, Kenton Station
London, Kew Gardens Station
London, Kilburn Park Station
London, Kilburn Station
London, King's Cross St. Pancras
London, Kingsbury
London, Knightsbridge Station
London, Ladbroke Grove
London, Lambeth North
London, Lancaster Gate Station
London, Latimer Road
London, Leicester Square
London, Leyton
London, Leytonstone Station
London, Liverpool Street Station
London, London Bridge Station
Loughton (Essex), Loughton
London, Maida Vale Station
London, Manor House
London, Mansion House
London, Marble Arch
London, Marylebone
London, Mile End
London, Mill Hill East
London, Monument
Moor Park (Herts), Moor Park
London, Moorgate Station
London, Morden
London, Mornington Crescent
PLUSBUS ticket available with train tickets for this station. Visit: www.plusbus.info to check fares & validity [9]
PLUSBUS is a cheap travelcard that you buy with your train ticket at any station ticket office or online. It gives you bus and tram travel on participating operators services to and from the rail station and around the whole urban area of town that's at the start &/or end of your train journey.

Buy PLUSBUS with your train ticket (at any station ticket office or online). For more information: www.plusbus.info
Affected Stops:
Bishops Stortford, Bishops Stortford Rail Station
Broxbourne, Broxbourne Rail Station
St Margarets (nr Ware), St Margarets (Herts) Rail Station
Waltham Cross, Waltham Cross Rail Station
Borehamwood, Elstree & Borehamwood Rail Station
Harpenden, Harpenden Rail Station
Hatfield (Herts), Hatfield (Herts) Rail Station
Apsley, Apsley Rail Station
Hemel Hempstead, Hemel Hempstead Rail Station
Hertford, Hertford East Rail Station
Hertford, Hertford North Rail Station
Hitchin, Hitchin Rail Station
Letchworth, Letchworth Rail Station
Baldock, Baldock Rail Station
Potters Bar, Potters Bar Rail Station
Radlett, Radlett Rail Station
St Albans, St Albans Abbey Rail Station
Stevenage, Stevenage Rail Station
Knebworth, Knebworth Rail Station
Ware, Ware Rail Station
North Watford, Watford North Rail Station
Bushey (Watford), Bushey Rail Station
Carpenders Park, Carpenders Park Rail Station
Garston (Watford), Garston (Herts) Rail Station
Watford (Herts), Watford High Street Rail Station
Watford (Herts), Watford Junction Rail Station
Brookmans Park, Brookmans Park Rail Station
Digswell, Welwyn North Rail Station
Welwyn Garden City, Welwyn Garden City Rail Station
Sawbridgeworth, Sawbridgeworth Rail Station
Rye Park, Rye House Rail Station
Theobalds Grove, Theobalds Grove Rail Station
Cuffley, Cuffley Rail Station
Berkhamsted, Berkhamsted Rail Station
St Albans, St Albans City Railway Station