Fast trains in Europe ended 2014 with a flourish. In December, Eurostar, which connects London, Paris and Brussels, started selling tickets for a year-round service to the Mediterranean starting this May. Poland introduced its first high-speed service, between Warsaw and Krakow; Serbia signed an agreement with China to build a fast line from Belgrade to Budapest; and Turkey inaugurated a line from Istanbul to Konya, having opened one between Istanbul and Ankara in July.

High-speed rail is controversial, as those now trying to introduce it to America know. This month, as work began on California's "bullet train" project, taxpayer groups condemned it as a monstrous waste of money.

Indeed, high-speed trains usually depend on public subsidy, yet their tickets are often unaffordable for many potential users, so they may not fill enough seats to avoid losses. The counter-argument is that over distances of roughly 180-500 miles, fast trains between big population centers are quicker and less polluting than most forms of transport. No one is keener on them than the European Commission.

Supported by the European Union and national subsidies, Europe has added more than 3,700 miles of high-speed track — on which trains travel at least some of the time at 155 miles per hour or more — to the 620 miles or so it had in 1990. Much more is under construction or planned. In 2015 a new line from Leipzig to Erfurt is due to open. A Milan-Brescia service may begin in 2016. By 2017 no fewer than four new French lines will come into service. The E.U., which is itching to spend more on infrastructure, plans to finance a $5.3 billion fast-rail link between Estonia, Latvia, Lithuania and Poland.

On a few routes high-speed rail has clawed market share from airlines: Eurostar now claims more than 75 percent of the combined rail/air market on its main routes; and Paris-Lyon and Madrid-Barcelona are also successful. Often, however, fast trains just take business from slow ones. Between 2000 and 2011, as high-speed lines opened across the E.U., rail's overall share of passenger-kilometers traveled was little changed, at 6.4 percent in 2011. Cars' share had barely budged, at 72.5 percent. Buses and coaches lost a percentage point, to 8.2 percent, with air travel (excluding flights to outside the E.U.) gaining more than a point, to 8.9 percent.

Some countries may have overextended their networks. In France, which launched the high-speed Trains à Grande Vitesse (TGV) in 1981, traffic, revenue and profit margins have fallen. To keep local politicians happy, TGVs stop at too many places, the national auditor concluded recently. Cheap flights and car-sharing, are siphoning off customers; SNCF, the national railway company that also manages TGV, has started a cut-price service in response.

Lack of competition among rail operators is another reason why high-speed rail is failing to win passengers from other means of transport. The E.U. is finding it hard to transform a bunch of national rail monopolies into a Pan-European market in which operators compete across borders. Three rail-reform packages since 2001 have made a start, but a fourth reform package, to liberalize further the market for passenger rail, has been held up and watered down by the European Parliament and national politicians.

So far national rail firms are preferring to collaborate than to compete. In September, France's SNCF and Germany's Deutsche Bahn renewed a joint venture, Alleo, which manages some high-speed services between the two countries. In December, Lyria, owned by SNCF and its Swiss counterpart, opened a new service between Lille and Geneva.

However, on a few of the busiest routes, competition may eventually take off. Deutsche Bahn has postponed but not abandoned a plan to send trains from Frankfurt through the Channel Tunnel to London. That means taking on Eurostar, in which SNCF owns a majority stake. Deutsche Bahn is also gradually pulling out of Thalys, a venture with SNCF and its Belgian and Dutch counterparts, in preparation for competing with them on those routes.

In domestic markets, too, things are moving. Europe's first private-sector high-speed operator is battling for market share in Italy. Nuovo Trasporto Viaggiatori (NTV, in which SNCF has a stake) started services in 2012 and reckons it now has over 20 percent of the business. It has struggled to compete with the state-owned incumbent, FSI, which controls the tracks. NTV has complained to the authorities about what it sees as FSI's dirty tricks; and it is hoping that a newly created independent regulator will insist on fair play.

The national rail operators would surely find it harder to rally political support to keep foreign rivals off their tracks if they were privatized. The Italian government is said to be considering a part-privatization of FSI. But Germany is thought to have quietly shelved a similar notion. And in France, especially, privatization seems out of the question.

However, competition from other forms of transport will only keep rising. Low-cost airlines are continuing to expand and in parts of Europe long-distance coaches are being liberalized. While high-speed rail remains in the grip of sluggish state monopolies, its chances of becoming a successful, competitive business look poor.

Copyright 2013 The Economist Newspaper Limited, London. All Rights Reserved. Reprinted with permission.