OBER-RAMSTADT (Germany) Thomas Schmieder pulled his Scania tractor-trailer with its house-painting load onto a highway south from Frankfurt. He then flicked a switch that you won't find on most truck dashboards.A contraption began to emerge from the roof outside the cab. It looked like a clothes-drying rack, with an upside-down sled attached to the top. A video display displayed the metal skids gently pushing against wires overhead as Mr. Schmieder drove on.As the diesel engine died, the cab became quiet and electric motors took control. Although the truck was still a truck it was now powered by electric motors.There is much debate about how to eliminate emissions from the trucking industry. Also, whether hydrogen fuel cells or batteries are the best way for big trucks to start their electric motors. A third alternative was tested by Mr. Schmieder. It feeds electricity to trucks while they drive using wires strung above roadways and a pantograph mounted on cab.
