IN 1952 John Betjeman, a poet, described Marylebone station as “like a public library from Nottingham which has unexpectedly found itself in London”. Others found its quaintness incongruous: British Rail, the nationalised owner of Britain’s railways until 1994, wanted to turn it into a bus station. Now it is buzzing with commuters. How the station not only survived but prospered, together with the railway line that runs out of it, suggest several arguments for rail reform.

Chiltern Railways is one of the fastest-growing rail franchises in Britain. Between 2003 and 2012 the number of journeys on the railway grew by 78%, rather faster than the 46% growth across the national network. It is expanding, too. Currently the railway runs between Marylebone and Birmingham and to commuter towns such as Aylesbury and High Wycombe. By 2016 it will also loop up from London to Oxford, introducing some competition to that route for the first time.

When the railways were privatised in the 1990s most lines ended up being run by established transport groups, such as bus companies. Chiltern’s went to a specialist management buy-out team. Its bosses proved innovative and entrepreneurial. By ploughing money into the network, and expanding it out to Birmingham, they managed to attract new customers, some of whom later switched from Virgin Railways, Chiltern’s more costly rival. “Under state ownership it would still be a commuting backwater,” says Bob Holland, managing director of Arriva trains, the company that owns Chiltern.

The line traverses a favoured spot. Chiltern’s route tracks the M40 motorway, cutting through wealthy commuterland. As more people moved out from London, and as the motorway became congested, London workers have piled onto the trains. The railway has also done well out of the growth of Bicester Village, a popular shopping centre in Oxfordshire.

Small, incremental changes ensured the railway flourished. Chiltern removed its first-class carriages in 2002, increasing the number of passengers that could be packed in as standard class. In 2011, instead of buying expensive new trains, the company extensively refurbished the old British Rail carriages from the 1980s that were still in use—at a third of the cost. When its franchise was extended Chiltern set up a shuttle service from Bicester North station to Bicester Village. This made the line more popular with tourists, particularly Chinese ones, who wanted a quick route to the shopping centre. The new line to be built in 2016 will include a stop at Bicester Village.

Unlike most rail operators in Britain, which run trains for five to seven years, when Chiltern was granted a franchise extension in 2002 it was for 20 years. This gives the firm scope for investment, argues Thomas Ableman, its commercial director. The longer franchise was also less prescriptive: although the Department for Transport (DfT) demands the company invest in the railway and regulates its fares, it does not force a timetable onto the railway, as it does with other services.

Longer franchises are also risky, however, and do not mean railway companies are guaranteed to invest generously in their lines. In 2011 Network Rail, the owner of Britain’s tracks, stepped in to help deliver an upgrade to increase the speed of the Chiltern line. Investment can be encouraged even through shorter terms, argue civil servants at the DfT. Competition could even be boosted by changing operators in the middle of a franchise. Operators could become shareholders in any investment, selling their share to the next franchise holder. When new rail contracts come up for renewal next year, it is unlikely that many will be particularly lengthy. Fewer may be as innovative as Chiltern Railways as a result.