BOGOTA, Feb 15 (Reuters) - Colombia's coal output in 2015 fell 3.5 percent from a year ago to 85.5 million tonnes, due to train transport restrictions and closures along the border with Venezuela.

The Andean nation, the world's fifth-largest exporter of the fuel, had produced 88.5 million tonnes in 2014.

"We are sure that despite the difficulties, the figures show a solid mining industry," Silvana Habib Daza, president of the national mining agency, said in a statement on Monday.

The sector struggled last year with court-ordered transport restrictions, including a ban on nocturnal train shipping on the Fenoco railroad, which serves U.S.-based Drummond Co, Glencore PLC's Prodeco unit and Murray Energy's Colombia Natural Resources.

A tribunal lifted the ban in November.

Closures along the border with neighboring Venezuela forced small producers to use more expensive transport to Colombian ports, rather than using Venezuelan ports closer to their mines.

Besides Drummond, Glencore and Murray, the country's coal sector includes Cerrejon, which is jointly owned by BHP Billiton , Anglo American PLC and Glencore.

(Reporting by Luis Jaime Acosta, Writing by Julia Symmes Cobb; Editing by Himani Sarkar)