[2] This section of 59.5 km (37.0 mi) between Pau and Bedous in France is used by TER Nouvelle-Aquitaine passenger trains, whereas the branch to Arudy from Buzy was converted into a cycle path after 2012.

The legal title to build the Pau to Oloron-Sainte-Marie section was given to the Chemins de fer du Midi on signing of a memorandum between the company and the Minister of Agriculture, Trade and Public Works on 10 August 1868.

Spanish project engineer Ramírez de Dampierre began construction of the Canfranc International Railway Station in 1923, and it was formally opened on 18 July 1928, in the presence of King Alfonso XIII of Spain and the president of the French Republic Gaston Doumergue.

From Pau, France, the line follows the Gave d'Aspe valley southward, reaching Bedous (altitude 405 metres (1,329 ft)) in relatively flat terrain.

After this it climbs into the Pyrénées Mountains, with an average gradient of 25 mm/m (1 in 40) to Etsaut, and then 43 mm/m (1 in 23) to the tunnel at Somport, where the line reaches its maximum altitude of 1,211 metres (3,973 ft).

On 20 March 1970, a nine-car train carrying corn left Pau for Canfranc (where there is still a large regional grain terminal), headed by two SNCF BB Midi locomotives, No.4227 and 4235.

[1] The accident, occurring two weeks before Good Friday, resulted in the railway service being replaced on a temporary basis with connecting buses from Bedous.

These economic pressures - in part driven by the General Motors (later PSA) plant located in Zaragoza - have in recent years resulted in heavy truck and car traffic on the roads of the upper Gave d'Aspe valley, and an increased number of accidents.

As a result, the French government placed pressure on SNCF to reopen the route to at least Bedous to allow the safe opening of the upper valley to tourists and also to service regional passenger traffic.

In September 2008, the major electrical substation which supplied power on the Pau to Oloron-Sainte-Marie section was turned off and removed to permit the commercial expansion of an industrial estate.

Subsequently, the Autonomous Community of Aragon acquired the Canfranc station from RENFE with a plan to restore and develop it as a catalyst (tourism, academic, economic) for the region.

After signing the memorandum, the Aquitaine Regional Council (ARC) commissioned SNCF to undertake preliminary studies on opening the 25 km (16 mi) section from Oloron-Sainte-Marie to Bedous, and to survey the whole line to Canfranc.

The SNCF reported that substantial work was required, including the replacement of 12 bridge decks, rebuilding of all road crossings to modern unmanned standards, and full renovation of all stations.

The hotel opens towards the end of January 2023, all the Spanish track is being equipped with sleepers convertible to standard gauge, and "with EU support it is hoped that the Canfranc line and station will be fully operational by 2026".