Just as suddenly as it materialized, a commuter rail demonstration project has evaporated.

The Utah Transit Authority was notified Thursday afternoon by Siemens Transportation Co. that a diesel-powered RegioSprinter rail car would not be available for a trial run on the Wasatch Front later this month."It's totally out of our control," said UTA spokeswoman Coralie Alder. "They need the vehicle, and they won't get it in time, by April 9th in Germany, and they are taking it this weekend."

The RegioSprinter is one of the latest innovations in rail technology and isn't even permitted for permanent use in the United States, at least not yet.

Siemens, which produces the lightweight rail car, sent a RegioSprinter from a storage facility in Boise to the Salt Lake Valley for a six-day demonstration before shipping it to Germany. The car arrived here Wednesday, but the company changed its mind 24 hours later because the German buyer requested immediate delivery.

"We had no choice. We are very disappointed," Alder said.

Siemens is the same company that is producing 23 light-rail vehicles for UTA's Transit Express (TRAX) system now under construction.