Single-phase generator The early generators for those single-phase traction networks are single-phase generators. Even with newer three-phase motors which were introduced to some modern trains, the single-phases transmission for traction networks survive their time and are still in use in many railways today. However, many traction power stations have replaced their generators over time to use three-phase generators and convert into single-phase for transmission. In the early development of hydroelectricity, single-phase generators played an important role in demonstrating the benefits of alternating current. In 1891, a 3,000 volts and 133 Hz single-phase generator of 100 horsepower was installed at Ames Hydroelectric Generating
Single-window system or economic borders. In a traditional pre-single-window environment, traders may have had to contend with visits and dealings with multiple government agencies in multiple locations to obtain the necessary papers, permits, and clearances to complete their import or export processes.A common definition of the term "single window" is: "A facility that allows parties involved in trade and transport to lodge standardized information and documents with a single entry point to fulfill all import, export, and transit-related regulatory requirements. If information is electronic then individual data elements should only be submitted once." The concept is recognised and promoted by several world