In order to demonstrate the effectiveness of its "portable" railway system, Decauville obtained the concession for the Tramway de Pithiviers à Toury (TPT) which ensured, until 1964, a large traffic in sugar beet as well as occasionally the transport of passengers.

Two years after the sugar beet episode, the success of the "Porteur Decauville" is such that elements were sold and delivered to the four corners of the planet, as the table below indicates.

By the First World War, the Decauville system had become a military standard, and the French and British eventually built thousands of miles of trench railway track.

[4] The Maginot Line was built with both external and internal 600 mm railways, the former served by combustion engines pulling supply trains from 1,435 mm (4 ft 8+1⁄2 in) standard gauge marshalling yards[5] behind the front, and the latter, served by electric locomotives taking over the loaded wagons inside the fortifications.

Tracks inside the fortresses went from the munitions entries in the rear all the way up to the fighting blocks, where ammunition loads were transferred to forward magazines using overhead monorails.

Similar feldbahn equipment was used in German South-West Africa where Otavi Minen- und Eisenbahn-Gesellschaft built the 600 mm (1 ft 11+5⁄8 in) gauge Otavibahn.

There are also open wagons to 1,435 mm (4 ft 8+1⁄2 in) standard gauge attached to normal trams for example for the transport of sand to prevent ice on the route or materials necessary for the maintenance of the lines.

A Decauville railway was used in the construction of La Plata, Argentina, in the 1880s, and transported dignitaries from the mainline trains to the site of the founding ceremony.

It was a 600 mm gauge rail built by the Province of Buenos Aires Railway, and departed from FCBAPE's Ensenada to Lomas de Tolosa (the first station established in the city).

[10] Also in Argentina, Decauville portable tracks and vehicles were used to transport passengers to Ostende, a city in Atlantic coast founded in 1913.

In the 1908 catalogue the range was greatly extended, to the detriment of the 600 track: Among traction equipment the five initial types were still present, but they had been refined.

At this time Decauville began to specialize in network equipment for colonies, leading to the appearance of very large metre-gauge vehicles (up to 32 tonnes, such as those intended for the French Sudan railway.

In 1951 they were bought by the Société nationale des chemins de fer français (SNCF) which assigned them to the Breton network.

In addition to railways, the company diversified very early on in many fields: agricultural machinery, electric motors, cycles and automobiles by offering the "carelle" in 1898, a voiturette driven in particular during the first Tour de France automobile by Fernand Gabriel (winner of the category), by Léon Théry (second then, still winner of the 1900 Coupe des Voiturettes and active with the brand from 1899 to 1902), and by Franz Ullmann (completed the lightweight class triple at the Tour de France, also present from 1899 to 1902), Paul Decauville competed in the first of the races in which his creations took part, in 1899 during the Nice-Castellane-Nice (it happened 15th.

[13] In the US, Henri Page obtained a few race podiums and three victories out of 10 and 15 miles (16 and 24 km) at Yonkers, Empire City, NY., for 1903 with a 40 hp (30 kW).

[14] In 1904 and 1905, William Hilliard, Guy Vaughn (mainly him, with about ten short races contested in 1905), Leland Mitchell and Huggins won several competitions on American circuits.

[15] From 1891 to 1902, Decauville produced six models of cycles, some of which were equipped to be able to travel on the railway, by adding a system made up of three tubes and a roller.