LONDON, Oct. 27 -- The London Underground system is the world's oldest, and it faces all the problems of other metro systems across the globe and some that are unique to London.
The job of tackling the challenge of the Underground, and of almost all of public transport in London from bicycles to buses, falls to Transport for London (TfL).
The challenges facing TfL are fourfold: the growth in demand; the age of the network; the size and congestion of the network; coordination with other transport modes, like bicycles and buses.
GROWTH IN DEMAND
London's population is currently 8.1 million, up from 7.1 million in 2001, and possibly reaching 9.4 million in 2022. Each day 5.5 million trips are made in London (2011), an increase of 1 percent over the previous year. The increase largely reflects population growth rather than a more fundamental change in travel behavior, according to TfL.
TfL said that Londoners are moving away from private transport toward public transport, walking, and cycling and cited figures for 2011, where public transport accounted for 43 percent of journeys, up from 42 percent in 2010 and 34 percent in 2000.
Public transport patronage grew strongly in 2011/12. There was a 4.8-percent increase in the annual number of journey stages and a 4.8-percent increase in passenger kilometers on public transport between 2010/11 and 2011/12.
Underground journeys grew particularly strongly, with 7.3 percent more passenger kilometers traveled.
AGE OF NETWORK
Mike Brown, the managing director of London Underground and of London Rail, said that London's network was unique and thus faced some unique problems.
He said, "London's Tube network is constructed entirely differently from any other one in the world because it is a hodgepodge of joining together old railway companies into one holistic system and that creates its own unique challenges."
The first underground line in the world is still part of the network. This central London section opened in 1863, and is currently part of the Metropolitan Line, one of 11 lines totaling just over 400 km of lines.
The network integrates with bus routes, and with surface trains. A new network, the Overground, of surface lines was created from existing lines including a former Underground line.
Brown, speaking to the Transport Committee of the London Assembly (LA) at the end of 2012, highlighted one example of old infrastructure being replaced.
He said the entire stock of old trains on the Metropolitan Line, which were built 50 years ago and which he described as "the oldest trains running on the UK mainland," had been replaced with new trains.
This is, however just one line.
Old stock works less well, and is more likely to break down and cannot be operated with the greatest efficiency.
Brown said, "It is certainly true that when you get to the very end of the life of a very old train, it is a big effort to just keep that trundling along on a daily basis as you are poised to introduce the entire new fleet."
New stock is now running on the Jubilee, Central and Victoria lines, but Brown said there "we are going to need to replace the Piccadilly line trains, which were built in 1973, and the Bakerloo line trains, built in 1972, quite soon."
The complex Northern Line is currently getting a signals upgrade to allow more efficient running and a greater number of trains, and the trains themselves will be new when the upgrade is completed next year.
SIZE, CONGESTION, DELAYS
Victoria Station at the rush-hour is a bad place to be. It is a major Tube line interchange sat beneath a large railway terminus in the central core of the city. The platforms are narrow, and passages long and winding. They were built for a less busy era.
Building work is underway to upgrade the interchange, but this itself creates congestion.
Passengers are regularly blocked from entering the station during rush hours because of overcrowding and the dangers that represents.
A recent upgrade of signaling and stock on the Victoria Line increased capacity by 20 percent, but across the network, which is already working at near capacity, the only solution is to build more lines.
The largest building project in Europe is building Crossrail, a line longer than 100 km stretching from the west of London to the east and passing through the center. When it opens in 2018 it will boost total network capacity by 10 percent.
Brown said that a third of delays on the Underground "are around so-called passenger action."
He said, "People do occasionally find themselves on the track either, unfortunately, because of a deliberate suicide attempt or to retrieve an object or some other foolish thing that people occasionally do."
Only one part of one line, the Jubilee Line extension which was built in 2000, has platform doors, which are standard for instance on new lines on the Beijing metro system, and the cramped sites of the stations, some of them 150 years old, means that platform doors will be difficult to install.
MODES OF TRANSPORT
The Underground is part of a complex city-wide transport network.
Other modes of transport face similar problems to the Underground, and elected officials on the LA are this week to take a look at the problems of overcrowding on buses.
A report estimated there would be an additional 167 million more bus journeys in 2022 than are currently taken.
Over a quarter of bus passengers surveyed by the Assembly said that their bus was already overcrowded, and the number of journeys by London bus has increased from 1.4 to 2.3 billion (64 percent) over the last 13 years.
London's population boom could see 9.4 million people living in the city by 2022. TfL's prediction that demand for bus travel will rise in line with population growth may be conservative, says the report. Over the last decade, bus journeys have risen at nearly four times the rate of population growth (4 percent against 1.1 percent).
Val Shawcross, Chair of the LA Transport Committee, said, "Buses are vital to keep London's transport network up and running. Every day 6.5 million journeys are taken by bus, more than twice as many as on the Tube. Demand for bus travel sees no sign of dwindling."