By the late 1980’s, Germany’s regional railroads were in dismal shape. They suffered many of the problems we face in the US — antiquated locomotive-hauled trains, and inefficient operating practices. It seemed inevitable that these lines would either be abandoned, or stagger on with ridiculous subsidies — much like Amtrak.
Then came German reunification, the 1993 railway reform act, and huge changes in the organization of Deutsche Bundesbahn, the former National Railway:
In the next 5 years, DB will invest about DM7,000 million in new and modern short-distance rolling stock. The entire fleet will be replaced modernized before the end of the century. Three hundred lightweight powered railcars have already been ordered within this program — the largest investment in German railway history. These cars are about 30% lighter than conventional cars. In addition, they are constructed mainly from proven components used in buses. They still cost more than a bus, but are equivalent in terms of maintenance expenses.
These cars are a decisive step to become able to compete with the automobiles and buses on side tracks at low loads. Many side tracks — especially in the new states of the Federation — which were hardly profitable because trains were drawn by locomotives, are enjoying a renaissance. The cars reach an average maximum speed of about 130 km/h and present a real alternative to the automobile.
These modern DMU operations have been wildly successful, and emulated all over Europe. A 2007 paper, published by Dietmar Bosserhof, looks at ridership gains from dozens regional rail projects. The entire paper is worth reading, but here is the money graph:
These ridership numbers are from a regional railway near Frankfurt. As you can see, ridership gains of 10x were achieved with targeted improvements in ticketing, frequency, and rolling stock.