PORTLAND – Train travel has emerged as an attractive option for drug dealers and other criminals seeking to move around the country, according to law enforcement officials.

With rail passenger service between Portland and Boston scheduled to begin next spring, authorities in Maine are bracing for an influx of crime.

“I can tell you, when the train comes, we’re expecting a lot more business,” said George Connick, supervising special agent for the Maine Drug Enforcement Agency. “A dealer will be able to just jump on a train down south and be here in an hour. It’s a definite concern.”

Investigators have yet to determine why two Wells, Maine, men involved in a deadly Dec. 12 shootout with Chicago police were traveling through Union Station, armed, wearing body armor and carrying $15,000 in cash.

But the fact that Andrew Ross, who was shot to death, and Daniel Wentworth, who was critically wounded, were moving about by train came as no surprise.

Authorities say train travel is attractive to criminals because of its relative anonymity.

Airports require that passengers show photo identification and pass through metal detectors, while car rental agencies demand a credit card and driver’s license. But travelers on trains, as well as buses, can pass from state to state with little notice, officials say.

Connick said police in Maine will need more training to identify passengers who may be using rail travel as a way to hide criminal activity. Passengers making long trips without luggage, or who expose unusually large amounts of cash when buying tickets, need closer watching, he said.

Ross and Wentworth came to the attention of Chicago authorities when they used about $700 in cash to buy their tickets before boarding the 12-hour train to Union Station, the first leg of a trip to Tucson, Ariz.

Suspicious, the ticket agent in Syracuse called ahead. A three-member drug interdiction team made up of a federal agent from the Drug Enforcement Administration, a Chicago police officer and an Amtrak security officer were waiting for them.

Police opened fire after Wentworth opened his jacket, exposing a .40-caliber Glock pistol, and Ross pointed his weapon at an officer’s head.

The DEA is leading the investigation in Chicago, but there is no evidence that Ross and Wentworth were involved in the drug trade.

“People carrying narcotics don’t typically wear bulletproof vests,” said Pat Camden, a Chicago police spokesman. “These guys were a couple of bad actors who were waiting for something to happen. Maybe we prevented something from happening in Tucson. Who knows?”