Patricia Williams looked up at the empty monorail track in front of the Las Vegas Convention Center and contemplated what should have been a quick, cheap and scenic trip.

"We're taking a taxi," complained the 42-year-old nail care consultant from Baldwin, N.Y., waiting with a friend for a $12 cab ride.

If the $650 million rail project were not months behind schedule, she could have whisked between the always-busy Convention Center and most of the Strip's biggest hotel-casinos for $3.

Instead, trains without passengers glide between stations on white elevated concrete rails above a side street behind the Las Vegas Strip.

The opening, originally scheduled for Jan. 20, was postponed to March -- and then to sometime this summer. The delays came after a drive shaft fell off a train during testing in January and technicians detected a glitch in a computer control system in February.

"It's not going to open until it's reliable and able to provide an efficient and safe mode of transportation," said Cam Walker, president and chief executive of Transit Systems Management, the private company that will operate the monorail for the nonprofit Las Vegas Monorail Co.

The drive shaft was fixed. But Walker said the software problem has proved more daunting: The control system is designed to keep a safe distance between trains running at up to 50 mph on the 3.9-mile track.

Once the system can handle seven trains at a time, it must run for 30 days before passenger service can begin. So far, up to five trains at a time were being tested, Walker said.

The delay is costing Canadian transportation company Bombardier Transportation and project partner Granite Construction Co. of Watsonville, Calif., about $85,000 a day in construction penalties, Walker said.

Helene Gagnon, a spokeswoman for Bombardier, said her company is less concerned about when the system opens than with making sure it runs properly.

"It's important to take the time and make sure we get it right," she said.

Nevada Gov. Kenny Guinn (R) approved funding for the rail system as a member of the state Board of Finance. A total of $644.3 million in tax-exempt bonds were sold -- to be repaid over 40 years with money made on fares and advertising.

Some Nevada lawmakers are concerned the state could be left holding the bag.

"I still think you need more oversight when the state's bond rating is on the line, and there have obviously been problems," said state Sen. Alice Costandina "Dina" Titus (D).

But Guinn and other state officials say if the project fails, the monorail company's insurer, not the state, will have to pay.

The company has sold ad space on four of the trains as moving billboards at $1 million each a year, and advertising rights at the Convention Center station to Nextel for $2 million annually.

With 35 million visitors a year to Las Vegas, Walker anticipates no trouble selling 19.1 million tickets a year.

Battista Locatelli, the singing owner of a tourist-oriented Italian restaurant beneath the Flamingo Road station, said he can hardly wait. "It'll be wall-to-wall good for business," Locatelli said.

Trains are scheduled at stations every four to five minutes. The trip from one end of the line to the other takes 14 minutes.

Williams, the New York nail care consultant, simply hopes the system is running when she returns for another trade show in July.

"It'll be cool to be able to view the city from there," she said.