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. In some languages, special terms exist, such as trolleyvoz (троллейвоз) in Russian or Oberleitungslastkraftwagen in German. 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 tend to use trolley poles for current collection, while higher-powered trucks, such as those in large-scale construction or mining, may exceed the capacity of trolley poles and use pantographs instead. Historically, trolleytrucks have seen use worldwide, particularly in the former Soviet Union. Today, they are still used for service roles in some cities in Russia and Ukraine, and as heavy-duty haulers in mines in North America and Africa. Because they draw power from the grid, trolleytrucks can use renewable energy. This has led to a modern revival of the concept in the form of "eHighways", where diesel–electric hybrid trucks use overhead lines on motorways to reduce emissions, with test projects underway in Sweden, Germany, and the United States.
History
Early developments
The concept of drawing power from overhead lines for a vehicle dates back to April 29, 1882, when Dr. Ernst Werner von Siemens demonstrated his Elektromote in Halensee, a suburb of Berlin, Germany. This experiment is considered the first demonstration of a trolley-powered vehicle in the world. The first application of the technology for freight transport began on July 10, 1901 in Königstein, Germany. Engineer Max Schiemann launched a 2.8 km line for a paper mill, utilizing electric tractors to pull trailers. His system, with its swiveling, spring-loaded trolley poles, became a standard for early trolley vehicle systems. Several other freight trolley systems were established in Germany in the early 20th century:
The Kalkbahn Grevenbrück (1903–1907) was used exclusively to transport limestone from a quarry to the Grevenbrück railway station. The Gleislose Bahn Monheim-Langenfeld (1904–1908) in Rhineland carried both passengers and freight. However, the heavy trucks quickly damaged the road surface, and the line was replaced by a railway. The Mühlenbahn Großbauchlitz (1905–1914) served mills in what is now Döbeln. The Hafenschleppbahn Altona (1911–1949) in Altona (now part of Hamburg) used electric tractors to tow wagons from the Elbe river port up a steep incline to the Altona railway station, replacing horse-drawn transport.
Interwar period and World War II In the 1930s, the Soviet Union began developing trolleytrucks. In Moscow, under the initiative of I. S. Efremov, director of the Second Trolleybus Park, the first serial trolleytrucks were created. They were equipped with extra-long trolley poles, allowing them to maneuver up to 6–7 meters from the overhead lines. The Yaroslavl Motor Plant began producing dedicated freight models, starting with the YaTB-4 in 1939, followed by the 8-tonne YaTB-5 in 1941. During World War II and the Battle of Moscow, a shortage of gasoline and the mobilization of conventional trucks for military use led to the expansion of trolleytruck operations. Old passenger trolleybuses were converted to freight use, and a dedicated freight trolley line was built along the Leningradskoye Highway to supply the city's Northern River Port. In Italy, a major trolleytruck system was built in 1938 to support the construction of dams in the Valtellina valley. Twenty trolleytrucks were used to transport cement and other materials for the construction of the San Giacomo and Cancano II dams. The system operated for over 25 years, until 1962.
Post-war era and Soviet dominance After World War II, the most significant developments occurred in the Soviet Union. To increase flexibility, a new type of vehicle was created: the diesel-trolleytruck, or duobus, which combined an electric motor for use under overhead wires with a conventional internal combustion engine for off-wire travel. This allowed vehicles to serve areas without full catenary coverage. Experiments were conducted to convert standard heavy-duty trucks into trolleytrucks:
In 1952, a dump truck based on the MAZ-525 was converted to electric power. It was equipped with two trolleybus motors with a total power of 170 kW. While it offered significant fuel savings, the constant need to relocate overhead wires in quarries and construction sites proved impractical. In 1961, a diesel-trolleytruck designated GTU-10 was developed based on the KrAZ-219 truck. It briefly operated on the famous Simferopol-Yalta intercity line before being converted back to a conventional truck. In 1964, BelAZ developed the BelAZ-7524-792, a 65-tonne capacity diesel-trolley hauler. Trials in 1965 showed its effectiveness, but the economic viability of such systems in open-pit mines was found to be dependent on the mine's depth (at least 300 meters) and stable haulage routes.
The most mass-produced and widely used trolleytrucks in the USSR were the KTG (Kiyevskiy Trollrybus Gruzovoy – Kyiv Freight Trolleybus) models, produced by the Kyiv Electric Transport Plant (KZET) from the 1970s. These vehicles were not conversions but purpose-built. Models like the KTG-1 (covered van) and KTG-2 (flatbed) became ubiquitous in cities with trolleybus systems, where they were used for maintenance, repair of overhead lines, and transportation of goods for the transit authorities. Many of these vehicles remain in service today in a utility role.
Applications by country
Austria Trolleytrucks were used in St. Lambrecht by the Nobel Industries dynamite factory from 1945 to 1951. They transported dynamite over the Alps after World War II due to material shortages that prevented the use of diesel trucks. By the 1950s, the trolleytrucks were replaced with diesel trucks, and some were converted into passenger trolleybuses in Kapfenberg. During the war, battery-powered trolleybuses were also used as tractors to pull freight trailers in Salzburg and Klagenfurt to conserve fuel. Since 2020, hybrid dump trucks have been used at the Erzberg mine, which can be operated emission-free via overhead lines on certain routes.
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