274 tube stations in the network - this includes station on the Metropolitan line for example which goes outside of London, but I hope this still answers the question! This figure does not include...
About a billion a year.
1 Imperial gallon = 4.54609188 liters = 4546.09188 ml
There are 8 pints to a gallon whether you are in the US or the UK.
The underground railway was NOT underground. It was a trail leading the black to safety.