This avoided the duplication of routes that was seen in the United Kingdom and meant that the large cities and towns were connected.

[1][2] In 1883, a proposal was put forward for a railway from Le Portel to Bonningues-lès-Ardres, in the Pas-de-Calais department.

It was decided at an early stage that the line would have to go through Saint-Martin-Boulogne, a village 2.3 kilometres (1.43 mi) from Boulogne which lies at an elevation of 114 metres (374 ft).

[3] In 1890, permission was given to the Compagnie des Chemins de Fer Économiques du Nord (CEN) to build three metre gauge railways in Pas-de-Calais.

[7] In 1911, a proposal was made to run a branch line from the Boulevard Daunou to Boulogne's waste incineration plant, on the banks of the Liane.

In November 1917, the British Army laid an 85 metres (93 yd) long siding at La Waroquarie to serve a camp at Ostrohove.

Following arguments re the provision of safety measures at the siding, from March 1918 a six-wagon train was run each night from Boulogne to La Waroquarie to bring in supplies.

[11] Following the war, the CF de BB was suffering due to a lack of maintenance of its locomotives and stock during wartime, leading to poor timekeeping.

[13] In the 1920s, extra trains were laid on from Boulogne to the Hippodrome de l'Inquéterie, a horse racing track between Blanc-Pignon and Souverain-Moulin.

French bureaucracy required that the CF de BB had to apply for permission to run these extra trains for each and every race meeting.

[14] On 31 December 1935, the department bought the concession to operate the CF de BB from the CEN.

In July 1939, six locomotives, 23 carriages, 32 goods wagons and five lorries were offered for sale by the department.

The job of compiling a full inventory hampered by the fact that the depôt was occupied by a motorised unit of the French Army.

The Pas-de-Calais department became a zone of special control, administered by the Oberkommando der Wehrmacht in Brussels, Belgium.

[18] In September 1942, the Marine Verpflugungamt (MVA) decreed that the line between Boulogne and Colombert was to be brought back into use.

[19] The railway ceased to be used for the transport of waste at Boulogne in April 1944,[15] due to its stock being requisitioned by the Germans.

These trains were to be operated by the Compagnie Générale des Voies Ferrées d'Intérêt Local (VFIL).

[21] In 1945, the mayors of the communes served by the CF de BB held a meeting, requesting the reopening of the line between Saint-Martin-Boulogne and Colembert.

VFIL stated that it was costing ₣9 million per year to run the freight service from Colembert to Bonningues-lès-Ardres.

[24] From the Quay Chanzy at Boulogne-Ville, the railway ran in the street, across the Pont de la Lampe over the Liane.

[21] The line continued around the Val Saint-Martin through Ostrohove and La Waroquerie to Saint-Martin-Boulogne, at an elevation of 114.4 metres (375 ft).

[27] Saint-Martin-Boulogne was the headquarters of the CF de BB, with a locomotive depôt and carriage sheds located near the station.

The line descended to Licques (67 metres (220 ft) before climbing to Bonningues-lès Ardres, where there was a junction with the Chemin de fer d'Anvin à Calais.