minutes - they are adjacent.
Yes, all London mainline stations have an underground station as well.
Romford doesn't have a tube station but the mainline station has a frequent service to London Liverpool Street. The nearest tube station is Upminster.
The London Underground does not go to Norwich, it only goes as far as the suburbs. Norwich has a mainline station with direct trains to London Liverpool Street.
The actual mainline station is all on one level (no steps or lifts). However, the underground station does not have lifts, but escalators instead.
Berkhamstead is too far out to be served by the tube. There is a mainline service to London Euston.
Assuming you meant public transport: You can get a Thameslink train from Gatwick Airport Train Station to St. Pancras station. Then a short walk to Euston station where you can catch a Virgin Trains service to Stafford (the main station in Staffordshire).
It is Westminster Cathedral. Its address is: 42 Francis St, London SW1P 1QW, United Kingdom It is not very far from Buckingham Palace. Victoria Station is the nearest underground station. It is also a major mainline station. See the links below.
London Paddington station was created in 1854.
By National Rail: Charlton mainline station.By Eurostar: St. Pancras.You would then need to catch a bus or the tube to get to the O2.
London St Pancras International Station.
London Bridge station was created in 1836.
Richmond station - London - was created in 1846.