There's been a change of plans in the design of the Loop Trolley cars.

Originally, the plan called for the trolley to use hybrid cars, which are battery operated in combination with power from overhead wires. However, the system will now be made up of heritage cars. Those are used trolley cars from the 1920s and 1940s that will be retrofitted for today's needs.

The heritage cars will require electric lines along the entire route, said University City Mayor Shelley Welsch in a blog posting on her personal website. Welsch is a member of the Loop Trolley Transportation Development District.

"I was told that progress has been made in making such lines less visually obtrusive than they have been in the past," she said on her blog. "This may mean that there could be double-track along the full route from the U City Lion (and tiger) Gate to the Missouri Historical Society, which is believed will cause less negative impact on car traffic along the route."

Joe Edwards, owner of Blueberry Hill and a driving force behind the Loop Trolley, said finances played a large role in switching trolley models.

"Early consultants from a number of years ago estimated the cost of the hybrid cars to be a little more than the regular ones but not that much more. It turns out it was at least three times as much," Edwards said at a recent meeting of the Loop Special Business District.

He estimates that each hybrid car can cost between $3 million and $4 million.

"That would have limited the number of cars we could have gotten for the system," Edwards said. It would send the project way over budget, Edwards said.

"To design a car like that (hybrid) for a public street use, it's not far enough along."

He said that the delay in technology could result in a delay in the project by a year or more. But, he said that it's fairly inexpensive to retrofit old cars with HVAC, and adapt the doorways for handicap accessibility.

There was also some concern that the hybrid cars would not have enough power and batteries to operate in areas without the overhead wires.

"If they die, then there is no way to get power to them. They'd have to be towed," he said.

Edwards said in five or 10 years, the hybrid cars could be added to the system.

Edwards said he hopes the consultants for design, engineering and implementation of the trolley system will be chosen and brought on board by mid-January.

He estimates groundbreaking on the system will happen by the end of summer or early next fall.

"Things are moving forward," said Edwards. "It's a good time."

The Loop Trolley is expected to run from near the lion gates in University City to DeBaliviere Avenue, and then south to Forest Park and back.