Shortly after a.m. on Sept. 28, 43 cars of an Illinois Central Gulf freight train derailed in front of patrolman Gary Stewart's house. Most of the cars were filled with chemicals, some of which exploded and blew out the windows of Stewart's house and left an emormous pit where the tracks used to be.

Two months later, Stewart sits in his patrol car, keeping the curious away as bulldozers move the dirt from a 4-foot-by-1,000-foot area contaminated with chemicals.

The cause of the wreck is under investigation by the National Transportation Safety Board. But it opened up the touchy issue of alcohol use on the nation's railroads after an Illinois Central Gulf clerk told federal investigators she was operating the train when it derailed because the engineer was drinking and could no longer sit up in his seat.

The investigation of this spectacular accident has spotlighted some of the most serious railroad safety issues of the 1980s: the threat hazardous materials can present to the public and the problem of substance abuse by train crew members.

What happened here could have happened as easily in the middle of large city, with much more devastating results. Almost 3,000 persons, including all of the 1,260 in Livingston, were evacuated from their homes for more than two weeks while chemicals spewed and seeped and burned and, at one time, exploded violently again, blowing out more windows and knocking another house or two off foundations. Only one person was reported injured.

The cleanup is continuing, and no one knows how much longer it will take or what it will cost. The National Transportation Safety Board has estimated the price tag at $12 million.

Robert W. O'Brien, director of corporate relations for Illinois Central Gulf, will not comment on that figure or make an estimate. However, he said, "It goes without saying it's a multimillion-dollar accident."

After bulldozers scrape away a layer of dirt, officials test to see if the next layer is contaminated. As the process goes on, the pit where the train fell has reached four feet deep and about 1,000 feet square. Only after state officials are satisfied that contaminated dirt is gone will they let the ICG fill in the hole and replace the track.

The last tank car hull has been pulled from the pit and stacked on other cars along what used to be a busy line. Their potentially lethal contents were either destroyed in the fire, pumped out or neutralized.

Almost every train moving these days includes at least one or two cars containing something toxic or explosive or both, and almost half of the cars on this train were carrying hazardous materials.

There have been major improvements in tank car protections in recent years, and the number of cars that released hazardous material in 1981 was only 110 out of almost 800 damaged in some way. In 1978, the worst recent year, the numbers were 220 and 1,200, according to the Federal Railroad Administration.

The alcohol issue is impossible to quantify. Federal Railroad Administrator Robert W. Blanchette called a special conference of railroad management and labor in June, before this accident, to discuss alcohol abuse.

"There are no reported facts," he said in his speech, "because the industry has absolutely no interest in reporting the facts of alcohol and drug abuse." Union members do not want to turn in fellow workers for disciplinary action, he said, and management does not want to risk liability suits.

Blanchette ordered a survey to see if he could obtain accurate information. "All 21 directors [of railroad-operated alcohol assistance programs] who were polled said that company officials considered on-the-job drinking a serious threat to safety," he said.

FRA statistics show that, of 5,781 railroad accidents last year, "human factors" contributed to or caused 1,597. Such factors include many things, only some of which involve sobriety.

According to the safety board, the Livingston wreck is the eighth major train accident since 1972 in which alcohol and other drugs are involved. The board does not investigate many minor accidents.

Alcohol became an issue this time when an office clerk told federal investigators she was operating the train when it derailed while the engineer and the head brakeman were drinking in the locomotive. Other railroad employes say the engineer and brakemen did not appear to be inebriated after the accident. No blood tests were taken.

However, a bartender and cocktail waitress have told investigators that the engineer and brakemen purchased drinks while awaiting a call for duty. On the basis of that testimony, O'Brien said, the engineer and brakeman were fired. The clerk has also been fired, but the railroad has given no reason.

The unions say the dismissals will be appealed. State criminal charges are pending against engineer, brakeman and clerk, all of whom have declined to comment and rejected an opportunity to testify at a safety board public hearing in nearby Baton Rouge last week.

The ICG insists that the spectacular fires and charges of alcohol abuse and an unauthorized person operating the train are obscuring a central point. "An empty gondola car, the 20th on the train, had a broken center pin," O'Brien said, and that, he said, caused the accident.

The center pin is the swivel point between car body and wheel assembly. When the car lifted from the assembly at the break point, the derailment began, O'Brien said.

Safety board officials are considering other factors, including a faulty air hose coupling, the fact the train was going over 40 miles an hour, at least 5 mph over the speed limit, and the way the train was handled.

Regardless of the outcome in this case, most railroads including ICG now have alcohol-treatment programs employes can enter voluntarily without jeopardizing their jobs. However, doing something to keep drunks out of the locomotive has been another matter.

Southern Pacific attempted in 1980 to give "intoxalyzer" tests to train crews as they reported for duty. That precipitated a two-day wildcat strike by the Brotherhood of Locomotive Engineers, which won a ruling that use of such devices was a change in longstanding practice and had to be negotiated.

"That program was an insult to a great many people who don't drink anything stronger than Pepsi," a union spokesman said. Southern Pacific said 4,000 persons, some relatives of employes, are enrolled in its alcohol treatment program.

Blanchette said at the June meeting that if labor and management did not devise a mutually agreeable program to address the problem of drunks on the railroad, the federal government would be forced to regulate. The safety board has been urging the FRA for eight years to adopt a rule similar to the one the Federal Aviation Administration uses for pilots, who may not drink eight hours before flying.

The Association of American Railroads and the Railway Labor Executives Association have held one meeting since Blanchette's prod to see if they can produce a recommendation.

Meanwhile, the bulldozers dig and patrolman Stewart guards the barricades on Rte. 190, which bisects Livingston.

Stewart is living in a trailer temporarily, as are several families whose homes cannot be occupied. Many others are pulling together the pieces after two weeks of living in motels or with friends. The railroad paid the bill and, according to those few interviewed in Livingston, has been responsive and helpful.

Stewart is anxious to fix his house and return home, although the building is only about 100 yards from the track. "I'm not worried about that," he said. "The odds are it'll never happen here again."