hydrogen fuel cell vehicle tramcar at an assembly facility in Qingdao. The chief engineer of the CSR subsidiary CSR Sifang Co Ltd., Liang Jianying, said that the company is studying how to reduce the running costs of the tram. Hybrid The Trieste–Opicina tramway in Trieste operates a hybrid funicular tramway system. Conventional electric trams are operated in street running and on reserved track for most of their route. However, on one steep segment of track, they are assisted by cable tractors, which push the trams uphill and act as brakes for the downhill run. For safety, the cable tractors are always deployed on the downhill side of the tram vehicle. Similar systems were used elsewhere in the past, notably on the Queen Anne Counterbalance in Seattle and the Darling Street wharf line in Sydney. Liquid fuel Hastings and some other tramways, for example Stockholms Spårvägar in Sweden and some lines in Karachi, used petrol trams. Galveston Island Trolley in Texas operated diesel trams due to the city's hurricane-prone location, which would result in frequent damage to an electrical supply system. Although Portland, Victoria promotes its tourist tram as being a cable car it actually operates using a hidden diesel motor. The tram, which runs on a circular route around the town of Portland, uses dummies and salons formerly used on the extensive Melbourne cable tramway system and now beautifully restored. Modern development In the mid-20th century many tram systems were disbanded, replaced by buses, trolleybuses, automobiles or rapid transit. The General Motors streetcar conspiracy was a case study of the decline of trams in the United States. In the 21st century, trams have been re-introduced in cities where they had been closed down for decades (such as Tramlink in London), or kept in heritage use (such as Spårväg City in Stockholm). Most trams made from the 1990s onwards (such as the Bombardier Flexity series and Alstom Citadis) are articulated low-floor trams with features such as regenerative braking. Design Trams have been used for two main purposes: for carrying passengers and for carrying cargo. There are several types of passenger tram: Articulated Cargo trams Double-Decker Drop-centre (or drop-center) Double ended and Single ended Low-floor Rubber-tired Tram-train Operation There are two main types of tramways, the classic tramway built in the early 20th century with the tram system operating in mixed traffic, and the later type which is most often associated with