DART officials took no chances during a test run Monday of the new Green Line light rail from Fair Park to downtown. Police were stationed at each intersection, and construction workers held up stop signs, just in case the crossing arms didn't go down.

Or just in case some motorist didn't realize a train was crossing the street.

"We're bringing trains back to an area that hasn't had trains for 50 years. There's a learning curve for motorists and for train operators," said Morgan Lyons, DART spokesman.

That span of the Green Line will open in September with four stations, at MLK Boulevard, Fair Park, Baylor University Medical Center and Deep Ellum.

On Monday, dignitaries and media were invited to ride along, and no one had to walk back. Frank Jennings, DART vice president of transportation, said he was on a test run three weeks ago when a software glitch caused the train to lose power before reaching the Fair Park station.

"We had to get a ride back," he said with a laugh.

Lyons said the line passed a round of tests last week in which the workers walked the trains through at less than 5 mph. The tests on Monday were at regular speeds, with workers monitoring the systems along the way.

"There were systems that we were still checking – making sure the substations talk to each other, making sure the signals are working and the crossing arms are going down," Lyons said.

Meanwhile, work is continuing on the four stations. Workers are laying brickwork at the MLK station and sod at the Baylor station.

At the Deep Ellum station on Good Latimer Expressway, a "Traveling Man" sculpture is under construction. The legs and hips of the 35,000-pound, 38-foot-tall sculpture are in place, and the rest will go up in the next week or two.

This is the first leg of the $1.8 billion Green Line, the longest light rail project under construction in North America.

Eventually, the Green Line will run from north Carrollton to Pleasant Grove. Along the way, it will serve Farmers Branch, northwest Dallas (including Love Field), the area around Parkland Memorial Hospital and UT Southwestern Medical Center, and the Dallas Market Center.

The full Green Line, 28 miles in length, is to be completed by the end of 2010. The line is the largest part of an expansion that will double DART's rail network to more than 90 miles by 2013.

The Orange Line, also under construction, will branch off from the Green Line near Bachman Lake to serve Irving and Las Colinas in 2011 and Dallas/Fort Worth International Airport by 2013.

Staff writer Bruce Tomaso contributed to this report.