The delayed and overbudget Elizabeth line finally opens on Tuesday.
Here, the PA news agency answers 10 key questions about what impact it will have on journeys.
– What area will the Elizabeth line cover?
It will run from Reading in Berkshire and Heathrow Airport in west London, to Shenfield in Essex and Abbey Wood in south east London, via the centre of the capital.
– Can I travel direct between those places from Tuesday?
Unfortunately not. The Elizabeth line will initially operate as three separate railways, with a change of trains required at Paddington and Liverpool Street.
– When will they be integrated?
That is expected to happen in the autumn.
– What is it currently like to travel through central London?
Many passengers travel by Tube on the Central line for east-west journeys across the capital.
These trains are often crowded and get hot in the summer due to not having air-conditioning.
– How will Elizabeth line trains compare?
They will be much more comfortable, featuring walk-through carriages, wi-fi, travel information screens and air-conditioning.
– How about the stations?
Ten new Elizabeth line stations will open in central London.
They will be lighter, brighter and larger spaces than the vast majority of London Underground stations.
– What will be the impact on journey times?
Many journeys within London will be quicker by the Elizabeth line than by Tube.
According to travel app Citymapper, platform-to-platform journeys between Liverpool Street and Paddington will be cut from 18 minutes to 10 minutes.
– How about if I am travelling longer distances?
Elizabeth line trains will stop at local stations, so journeys will be slower compared with the fastest mainline services between locations such as Reading and Paddington, or Shenfield and Liverpool Street.
But once the three sections are integrated, many passengers will benefit by not having to change between trains and Tube services.
– What impact will the new line have on capacity?
It will boost rail capacity in central London by 10%.
– How much will it cost to use?
Elizabeth line journeys in central London will cost the same as equivalent Tube fares.
Fares on services in the outer sections currently operated by TfL Rail will be unchanged.