A trolleytruck (also known as a freight trolley or trolley truck) is a trolleybus-like vehicle used for carrying cargo instead of passengers. A trolleytruck is usually a type of electric truck powered by two overhead wires, from which it draws electricity using two trolley poles. Two current collectors are required in order to supply and return current, because the return current cannot pass to the ground (as is done by streetcars on rails) since trolleytrucks use tires that are insulators. Lower powered trucks, such as might be seen on the streets of a city, tend to use trolley poles for current collection. Higher powered trucks, such as those used for large construction or mining projects, may exceed the power capacity of trolley poles and have to use pantographs instead. Trolleytrucks have been used in various places around the world and are still in use in cities in Russia and Ukraine, as well as at mines in North America and Africa. Because they draw power from the mains, trolleytrucks can use renewable energy sources – modern trolleytrucks systems are under test in Sweden and Germany along highways using diesel–electric hybrids to reduce emissions. Use throughout the world Austria Trolleytrucks were used in St. Lambrecht, Austria by the Nobel Industries dynamite factory from 16 November 1945 to 21 April 1951. Trolleytrucks were used to carry dynamite over the Alps just after World War II due to the shortages of material that for a time prevented the use of diesel trucks. In the 1950s the material shortages had been alleviated so the trolleytrucks were replaced with diesel trucks and the former power lines were taken down. Some trucks from the abandoned line were reconverted to trolley buses and used along streets in Kapfenberg. Bulgaria A Ukrainian built trolleytruck started service in Pleven, Bulgaria in 1987, but that truck may no longer be in service since it is stored in the trolleybus depot. Canada The Québec Cartier Mining Company used trolleytrucks in its iron ore mine in Québec from 1970 until 1977 when the iron ore deposit was exhausted and the mine closed down. The power supply for this remote mine was a power plant taken out of a diesel electric locomotive. As of 2022 the Copper Mountain Mining Corporation operating at Copper Mountain, British Columbia is converting its diesel-electric haul trucks to trolley assist for the climb out of the pit, with power