Oyster PAYG on National Rail

http://www.nationalrail.co.uk/times_fares/london/OysterPAYG.pdf

Oyster PAYG has always been valid on National Rail (NR) on lines where Underground Tickets were historically valid, which are basically lines that double the Underground -eg Barking <--> Fenchurch St and Stratford<--> Liverpool Street. But the NR PAYG network is growing, partly because when franchises are renewed the franchise includes a requirement to accept it, partly because TfL are funding Oyster equipment at NR stations and partly because TfL now runs NR lines -ie the London Overground. Some NR companies have willingly accepted the improvement, and others are reluctant. It is worth keeping an eye on the map for additions.