I might be wrong, but I think that excluding the Waterloo & City, only the Met and District don't connect to every other line (or, in other words, that the Bakerloo, Central, Circle (if Monument counts), Jubilee and Northern lines connect to every other line). As to why some sources are wrong, I'm not sure beyond human error.Why do online answers still say that only the Jubilee line connects to all other lines? I believe that Northern also does? For clarity, I am only referring to Underground, not DLR or Overground
I wonder if it goes back to when the East London Line was part of LU? In which case the Jubilee would be right but only for 6ish years
There is also a physical connection between Central and Metropolitan lines from the depot at Ruislip, used mainly for engineering trains.Passenger connections and rail connections are different
A F A I K, the only surviving rail connection with the Central Line is with Network Rail at West Ruislip,
although l remember the physical connection with the District at Ealing Broadway in the 1970s
There were many political noises from the Uxbridge area once (1970s/80s) for some Central Line trains running to Uxbridge, via a connecting chord at Ruislip
but that is outside the scope of this thread.