Cable-car tram. 19th century cut-away engraving of a cable car tram in a street of San Francisco, USA, showing the underground cable used to pull the tram. Such light urban railways can provide a rapid means of transport around cities. The cable car was made possible by Andrew Hallidie's 1869 invention of a grip that could grasp a continuously running cable. A cable car tram system was introduced to San Francisco in 1873 because the city's steep roads meant that the wheels of a self-powered tram could not get enough grip on the rails to drive it uphill.