With the northeastern railroad Conrail merged into history at midnight, train service on the East's two remaining rail giants began nearly flawlessly today despite a human error that delayed the start-up of Norfolk Southern's computer systems for hours.

Trains began running as scheduled on both CSX Transportation and Norfolk Southern this morning on Day One of a new railroading order in the East. The two railroads split the federally planned Conrail roughly in half, leaving them as the two dominant railroads east of the Mississippi.

Some trains continued running, but no trains could be dispatched after computer systems were shut down Monday afternoon for an overnight transfer of voluminous amounts of data from the old Conrail Inc. computers to the Norfolk Southern Corp. and CSX Transportation Inc. computers.

CSX appeared to have a textbook start-up despite the most complicated melding of computer systems and train operations in railroad history. A smiling CSX Operating Vice President Ron Conway arrived at the former Conrail headquarters building this morning to congratulate his troops, and top CSX officials began calling politicians, union leaders and others throughout the East to thank them for their help during more than a year of intense merger planning.

"All of the problems appear to be minor," Conway said. "It's almost as if we have to go around looking for problems. I couldn't be more pleased with how these IT [information technology] people pulled this off."

Computers on lines in the New Jersey-New York industrial "shared access area," which will continue to be called Conrail, also came on line smoothly early this morning.

But Norfolk Southern technicians, working on another floor of the building, blundered during the night by loading test files into computers rather than a mass of real-time files from the former Conrail. An official, who asked not to be named, said the error was noticed only after the computers started producing "goofy data." Computers that had been scheduled to be operating early in the morning were brought on line after noon. Later in the day, an official said remaining computer problems were clearing up faster than anticipated.

Railroads today operate as much on computers as on rails, and the melding of Conrail data into the Norfolk Southern and CSX systems was considered one of the most difficult tasks of the merger.

In the meantime, Norfolk Southern fell back on one of the many contingency plans developed during the intense planning period, dispatching trains on schedule the old-fashioned way, with paper records and orders. Technicians then were faced with the large task of getting masses of paper data into the computer.

Norfolk Southern officials said all train operations were proceeding according to plan. All 200 planned train starts for the first 24 hours of operation appeared to be on track as scheduled, officials said.

The task for both railroads now is to continue operating the railroad efficiently. Union Pacific Railroad Co.'s bumpy merger with Southern Pacific Rail Corp. in 1996, and the resulting disruption to shipping around the country, did not manifest itself until months after the merger. Much of the planning for the Conrail merger was driven by fear of making the same mistakes as Union Pacific. Congress and federal regulators are watching closely to determine whether railroads in the East will face the same or similar problems.

The merger already has led to rate wars between the two railroads, especially in the New York-New Jersey industrial area, which will have its first rail competition since Conrail was formed April 1, 1976, from the lines of bankrupt eastern railroads.

Norfolk-based Norfolk Southern gained 58 percent of Conrail's lines, including a heavy-duty main line from New York to Chicago through Pittsburgh. Richmond-based CSX gained 42 percent of Conrail, including its other New York-Chicago main line through Buffalo and Cleveland.

One snip of the old Conrail will be left when the changeover is complete. Norfolk Southern and CSX will share industrial trackage in northern New Jersey and in Detroit. The New Jersey shared access area will be called Conrail, and its switching locomotives will be painted in the old Conrail colors of blue and white.

CAPTION: How Conrail Is Being Divided (This graphic was not available)

CAPTION: Train buffs on the front porch of the Station Inn, a bed and breakfast in Cresson, Pa., watch the final runs of Conrail locomotives over the weekend.