Little is really known about these trains since, as they always belonged to a private company, the information about their activity almost disappeared with the railway itself.

The first railway projects that affected the area, dated around 1890, had to do with a railway from Haro to Pradoluengo. Later plans developed possible branches to Burgos from Belorado. In 1891, a branch line was proposed that would originate in in Casalarreina and run to Ezcaray.

Finally, after many comings and goings with projects and concessions, the only existing railway in La Rioja Alta (in addition to the broad-gauge route of the Ebro Valley) was the one in question, Haro-Ezcaray. The first train ran on the line on July 9, 1916. However, as a fine narrow (metric)-gauge railway in a rural area, its future was very modest and its staff never exceeded 85 employees. The train was known in the area as "El Bobadilla," in the diminutive form, in comparison to Norte’s large trains with which it linked up in Haro.

In 1956, during one of the railway's best moments, it transported 34,000 tonnes of goods and 210,000 passengers. These figures soon declined spectacularly due, on the one hand, to the depopulation of the region and, on the other, to competition from cars, buses and trucks.

The railway gradually became less and less profitable and was finally closed one cold morning on January 15, 1964.