The Metropolitan Atlanta Rapid Transit Authority (MARTA) is in the process of procuring cars. These cars are of welded aluminum extrusions, 75 feet long, and are powered by a chopper modulated 750 volt third rail propulsion system. Certain unique features are discussed in detail, including the method of body construction, reliability, noise levels, the cooling of propulsion equipment, and auxiliary voltage regulation. The test program is outlined and the significant results to date summarized. Most difficulties have been of a second order nature, but testing has taken longer than had been anticipated. A recommendation is made to provide more time for testing on future procurements, or to plan operations using other than new equipment.