A sophisticated drug-smuggling tunnel equipped with a rail system and electricity was discovered near the US-Mexico border in California on Friday, authorities said.

The subterranean passage, one-third of a mile long, linked Tijuana to a warehouse near San Diego’s Otay Mesa border, federal officials announced Monday.

The tunnel also had ventilation systems and reinforced walls and is 61-feet deep and 4-feet in diameter.

As part of the bust, 1,762 pounds of cocaine, 164 pounds of meth and 3.5 pounds of heroin were recovered.

Six people were charged with cocaine trafficking, and two of those six were also charged with meth and heroin trafficking, authorities said.

Authorities ultimately uncovered the tunnel after they pulled over vehicles they saw coming and going from a home and the warehouse. During those traffic stops, boxes of drugs were found, prosecutors said.

Authorities found no other drugs at the warehouse when they raided it, but spotted a tunnel opening carved into the cement floor, federal prosecutors said.

“There is no more light at the end of this narco-tunnel,” Randy Grossman, US attorney for the Southern District of California, said in a statement. “We will take down every subterranean smuggling route we find to keep illicit drugs from reaching our streets and destroying our families and communities.”

It’s unclear how long the route had been used, but it’s not uncommon for dealers to use tunnels to transport illegal drugs.

“The San Diego law enforcement community throughout the years has consistently shown its ability to detect and remediate tunnels while bringing those responsible to justice,” Homeland Securities Investigations San Diego Special Agent in Charge Chad Plantz said in a statement.

In January 2020, the US announced it discovered the longest known drug tunnel at the time that stretched three-quarters of a mile between Tijuana and San Diego. The tunnel had a rail system and elevator, according to US Customs and Border Protection.