The line from St. Brieuc Centrale to Plouha opened on 20 June 1905 and closed on 31 December 1956. St. Brieuc Centrale – St. Brieuc Ouest opened on 11 April 1907, giving a total length of . The line was very close to the coast in places, and heavily engineered, with thirteen bridges in . The main bridges were the Pont de Gouëdic and Pont de Rohannec'h at Saint-Brieuc, the Viaduc de Souzain between Saint-Brieuc and Plérin, the Viaduc de Colvé, Viaduc de Tosse-Montagne and Viaduc de Grognet and the Viaduc de la Horvaie at Plérin, the Viaduc du Parfond du Gouët ( long, high), the Viaduc de la Hasée, Viaduc de Beaufeuillage and Pont en biais sur l'Ic at Binic, and the Viaduc de Ponto and Viaduc des Pourrhis at Étables-sur-Mer.
