SAN DIEGO — A tunnel designed to smuggle drugs from Tijuana, Mexico, to San Diego was equipped with lighting, ventilation and an electric rail system, U.S. authorities said Thursday, making it one of the most sophisticated secret passages discovered along the U.S.-Mexico border.

Authorities seized 8½ tons of marijuana and 327 pounds of cocaine in connection with the tunnel’s discovery, according to court records. Three men who authorities say worked as drivers were charged Thursday with possession of marijuana and cocaine with intent to distribute. U.S. Attorney Laura Duffy said they face prison sentences between 10 years and life if convicted.

The tunnel, which zigzags the length of nearly six football fields, links warehouses in Tijuana and San Diego’s Otay Mesa industrial area. The area is filled with nondescript warehouses, making it easier to conceal trucks being loaded with drugs.

The tunnel was shut down Wednesday night, before any drugs made it through undetected, authorities said. Federal agents had the San Diego warehouse under surveillance after being tipped off by an informant who told them that operators bought drills and other construction equipment in August and September.

As U.S. border security has heightened on land, Mexican drug cartels have turned to ultralight aircraft, small fishing boats and tunnels. More than 75 underground passages have been discovered along the border since 2008, designed largely to smuggle marijuana.

The tunnels are concentrated along the border in California and Arizona. San Diego is popular because its claylike soil is easy to dig. In Nogales, Ariz., smugglers tap into vast underground drainage canals.

The tunnel is the eighth major passage discovered in San Diego since 2006, a period during which Mexico’s Sinaloa cartel has solidified its hold on the prized smuggling corridor. Authorities said Wednesday’s tunnel was the first in the San Diego area that was found to be used for cocaine.

The passage was about 35 feet underground, 4 feet high and 3 feet wide, said Derek Benner, U.S. Immigration and Customs Enforcement’s head of Homeland Security Investigations in San Diego. Authorities said the zigzag route suggests that excavators veered off course several times.