Network Rail will embark on almost £12bn of investment on projects designed to relieve congestion - including more seats, extra services and longer and faster trains - as part of an overall £35bn spending programme over the next five years. Here are the main schemes.
The new Blackfriars station will span the River Thames
The number of carriages on the north-south route through London will rise from 64 to 288 per hour, an increase in seating capacity of 3,500 to 17,000.
The first stage on the northern part of the route will see 50% longer trains, dozens of stations upgraded and a new station built at Blackfriars, all in time for the 2012 Olympics.
The second phase will see major bottlenecks removed and new station facilities at London Bridge, to provide increased capacity by 2015.
The Crossrail route will include an underground section
Main construction will start in 2010 on the major east-west link across London which is due to open in 2017.
The route goes from Maidenhead and Heathrow airport in the west, underground through the centre of the capital between Paddington and east London, and into Essex and Kent in the east.
Each train will be able to carry more than 1,500 passengers.
Crossrail is the UK's biggest transport project since the Channel Tunnel, with an overall cost of £16bn.
BIRMINGHAM NEW STREET
Birmingham New Street is part of a wider regeneration project
The first phase of work is due to transform one of the UK's busiest stations by tackling overcrowding.
A new concourse will be more than three times its current size and facilities for passengers will be modernised.
The station is served by 1,250 trains a day despite being designed to cope with just 650.
The scheme is part of the Birmingham Gateway city centre regeneration project, which will create 3,000 jobs.
A new passenger line will be built from from Airdrie in North Lanarkshire to Bathgate in West Lothian after the route remained closed for 50 years.
A cycle path will be constructed leading to stations along the line to try to encourage the use of public transport.
A new nine-mile rail link will connect Glasgow Central with a purpose-built station at Glasgow airport. Trains will call at Paisley Gilmour Street en route.
LONDON KING'S CROSS
The original 1851 facade at King's Cross will be part of the rebuilt station
The project will triple the size of the concourse area and provide more space and shops by 2013 to help the station cope with its 47 million passengers a year, which is expected to rise by another 10 million over the next decade.
There will be a glass and aluminium concourse roof, an extra platform and improved links to Tube and other main line services.
New tracks and platforms will be added at the Berkshire station to improve train speeds, reduce delays and ease overcrowding.
EAST COAST MAIN LINE
Projects include remodelling junctions, removing or altering level crossings and works to bridges and platforms.
The result will be increased capacity, faster and heavier trains, and higher and wider freight containers.
The Edwardian roof over the station's platforms 9 to 12 will be restored, resulting in a lighter and brighter environment.
Network Rail is considering the construction of a short section of new track north of Nuneaton station in Warwickshire on the West Coast Main Line to help freight traffic.