The most important transportation system is the Congo-Ocean Railroad. Completed in 1934, the 510-km (317-mi) line runs between Brazzaville on Pool Malebo and the ocean port of Pointe-Noire. In the course of descending the Mayombé Escarpment, it crosses 172 bridges and goes through 12 tunnels. To relieve congestion on this stretch, a 91-km (57-mi) line was completed between Bilinga and Loubomo in 1985. The 285-km (177-mi) Comilog rail line was completed in 1962 to transport manganese ore extracted at Moanda, Gabon, from M'Binda on the Gabonese border to the Congo-Ocean line at Mont-Bélo. This traffic was expected to end in the late 1980s with the completion of a railway in Gabon that will transport the ore to the port of Libreville. In 2002, the country's total rail trackage was 894 km (555 mi), all narrow gauge.
Dense tropical forests, rugged terrain, and swamps, together with a hot, humid climate and heavy rainfall, make construction and maintenance of roads extremely costly. In 2002 there were about 12,800 km (7,954 mi) of highways, but only about 1,242 km (772 mi) were asphalted, and it was considered extremely risky to venture more than 150-200 km (90-125 mi) from Brazzaville because of the poor road conditions. A Brazzaville-to-Duesso road was completed as far as Owando in the mid-1980s. In 2000, about 29,700 passenger cars and 23,700 commercial vehicles were in use.
River transportation is managed by the state-owned Trans-Congo Communications Agency. There are up to 1,120 km (696 mi) of navigable waterways on the Congo and Oubanui rivers. The river port of Brazzaville, which is the junction point of the Congo-Ocean Railroad and the Zaire-Oubangui river system, is an important center for trade with the Central African Republic, Chad, and the DROC. A ferry connects Brazzaville with Kinshasa, DROC. Pointe-Noire is the Congo's only seaport and the terminus of the Congo-Ocean Railroad.
Because of the great distances and the inadequacy of land transportation, air travel and air freight services are rapidly expanding. Brazzaville (Maya-Maya) and Pointe-Noire airports are the hubs of a network of air routes that connect the four equatorial republics with several European cities. The state-owned Lina-Congo holds a monopoly on domestic routes. The Congo is a member of Air Afrique, of which it owns a share. Air Afrique and Union des Transportes Aériens (UTA) are the chief international carriers. In 2001, 95,200 passengers traveled on scheduled domestic and international flights.