Chattanooga's 138-year public transportation heritage is a complex and colorful conglomeration of some 32 companies that were initially comprised of horse-drawn streetcar lines. They were later upgraded to electric traction operations, steam dummy lines, and finally to the motor-coach buses of today. Chattanooga's transit story has been unique from its inception. Few cities have had any connection to the incline railways that were constructed in this mountainous city, one of which, the famous Lookout Mountain Incline Railway, is still in daily operation. Today's CARTA transit system has innovated one of the largest fleets of battery-operated electric buses, which other transit companies use as their model for comparison.