The following is based on reference 8 :. The practicalities of installing and operating a trolley assist truck haulage system at Palabora was confirmed by a feasibility study in Acting on the study's recommendations, a three-phased approach was adopted. Phase I was a test program to prove the technical and operational feasibility of the system. The trolley line design was of compound catenary construction and totaled meters in length. Two single copper contact wires were used, one for each of positive and negative supply.
Electric power was provided to the overhead lines via a roadside rectifier substation, which was designed along the lines of modern railway practice having a continuous output of 5, kW at 1, volts DC. Current collection from the overhead trolley line to the trucks' onboard equipment was via 2 trolley poles mounted on a platform supported immediately ahead and above the driver's cab.
Upon selecting trolley mode, the poles would automatically unlatch from their stowed position and extend upward by the action of pneumatic cylinders. An "entrance pan" was used to guide the trolley pole onto the conductor wires.
In June of the Phase I trolley line was commissioned and the first converted truck made its maiden run. Although the system was functional and achieved many of the design goals, it was decided that the current collection system needed improvement. Thus, the trolley poles were replaced with two railway type pantographs which were much larger and heavier than the trolley poles. The trolley line was converted to accommodate this concept.
By October all 75 of the ton Unit Rig trucks were converted to trolley, and 2. Unit Rig M MLT Euclid R Lots of Trucks. The following is based on reference 12 :. ISCOR conducted a trolley-assist feasibility study.
The incentive was the unrealistic escalation in the cost of diesel fuel, and the appeal from the South African government to reduce the use of fossil fuels. Tests and economic evaluations proved the system to be technically feasible and economically attractive.
Construction of 7. Although the truck conversions of the GE drive system were similar to what was done at QCM Lac Jeanine mine in Canada, the unique operational requirements at Sishen rendered the already proven trolley pole system unacceptable. Minimum loss in truck mobility and flexibility was required.
Overhead lines and substations were required to be of a relatively light construction and portable, enabling fast and easy repositioning of a line with no loss in material. These unique specifications set the base for the design of the Sishen system. The overhead line was constructed using steel I-beams mounted on base plates.
The masts were erected at about a 50 meter span and the base plates covered with approximately 12 tonnes of iron ore to keep them stable. It was decided to suspend each polarity of overhead conductor wire from an independent cantilever arm. These conductors were kept under constant tension by means of weights acting through a pulley tensioning arrangement.
For each overhead conductor, a standard grooved copper railway conductor was used. To obtain the necessary current carrying capacity, 2 of these conductors were used in parallel for each polarity. The rectifier stations consist of an 11 kV to V three phase transformer and a three phase diode bridge rectifier. The output capacity of each station was adequate to supply 1 truck. A scaled-up version of the railway type of pantograph was used to collect the current from the overhead lines.
Each pantograph head is 3 meters wide, equipped with 2 strips of current collecting graphite brushes in parallel. With the Sishen system, a truck can exit at any point along the line, pass a disabled truck that is blocking the line and re-enter at any point. ISCOR has been a great proponent of trolley assist, and has continually developed innovations in overhead lines, substations and pantographs.
Poles Raised Ready to Enter Trolley. By , interurban operators had laid 18, miles of track around the United States. Downtown Sandusky, Ohio, was a parking lot for passengers switching to the interurban line. Courtesy of the Ohio History Connection. Though rare in the impoverished and mostly rural Deep South, lines proliferated elsewhere, especially in the heartland.
And there were lots of industries. Operators financed construction by selling stocks or bonds to utilities, bankers, industrialists, politicians, developers, and individual investors. The biggest system was the Pacific Electric Railway. The Pacific Electric was the creation of rail tycoon, developer and art collector Henry R. Huntington, nephew of Colin Huntington, a founder of the Southern Pacific.
The younger man, who had apprenticed under his uncle for years before going out on his own, saw real estate and rails as intertwined—wherever he built his lines, he built houses, and vice versa. Huntington helped introduce surfing to California by bringing Hawaiian board ace George Freeth to Redondo Beach in He also founded the art musem bearing his name. Pacific Electric cars climbed a steep grade to the summit of Mount Lowe, California. Library of Congress.
The Pacific Electric largely spurred the growth of suburban Los Angeles. Nationwide, if interurbans had a rival, it was the railroad. Electric interurbans were faster and cleaner than wood- and coal-powered steam trains belching smoke and cinders.
At a rural hamlet the train might stop a few times a day. Interurbans passed by at least hourly. Light, self-propelled interurban cars offered flexibility. The routes crossed near an apiary in Marysville, California. The apiary is still around.
Harriman applied his influence with regulators to harry Huntington. In , following a bidding war, Huntington made Harriman a partner in exchange for several benefits, including rights to the key Sixth Street rail franchise in Los Angeles. Hellman sold his shares in In , over three million horses worked in American cities. They produced some 30, tons of manure every day. This was a major urban concern, used by promoters of motorized vehicles to sell the idea of trucks and automobiles to the public.
Washington had always been known for its wide streets, and beginning in the s the District government invested in better street surfaces. In the downtown area, gravel was eventually replaced with stone blocks or asphalt.
Pennsylvania Avenue between 7th and 8th Streets, N. Street vendor on Pennsylvania Avenue, N. Public Library. Street vendors sold foods and services to residents. This practice sometimes put vendors at odds with neighborhood shopkeepers. Overman Wheel Co. The s saw a great boom in bicycling. As the first personal mechanical mode of transportation, the bicycle often gave both men and women a thrilling sense of freedom.
Cleveland Model 69 Bicycle, Horse-drawn carriages were common on Washington streets in By the time this photo was taken in the s, automobiles had changed the city streetscape, and the carriage was becoming a rarity. West Virginia Senator and Mrs. Nathan B.
Scott with their automobile in front of the U. Capitol, about Around , trucks and automobiles began to appear on city streets. Only the wealthy owned cars, which were used mostly for recreation and short trips. Washington, one of many American cities that built new electric streetcar systems, began converting from horse and cable cars in Trolley lines created the modern suburb and the commuter and enabled people to live farther from their jobs in the commercial center of the city. In Washington, the streetcars were privately owned and run.
Real estate developers built many lines to promote new neighborhoods. Passengers wait to board streetcars at 11th and F Streets, N.
In Washington, two men operated a streetcar. While the District did not pass a streetcar Jim Crow law, unwritten social customs segregated blacks and whites on the streetcars and in other public places.
There had long been horse-drawn carriages in America to take people where they wanted to go. What was new and different about the omnibus was that it ran along a certain designated route and charged a very low fare. People who wanted to get on would wave their hands in the air.
The driver sat on a bench on top of the omnibus at the front, like a stagecoach driver. When people who were riding inside wanted to get off the omnibus, they pulled on a little leather strap. The leather strap was connected to the ankle of the person who was driving the omnibus.
Horse-drawn omnibuses ran in America cities from until about The streetcar was the first important improvement over the omnibus. The first streetcars were also pulled by horses, but the streetcars rolled along special steel rails that were placed in the middle of the roadway instead of traveling along regular streets. The wheels of the streetcar were also made of steel, carefully manufactured in such a way so they would not roll off the rails. A horse-drawn streetcar was much more comfortable than an omnibus, and a single horse could pull a streetcar that was larger and carried more passengers.
The first streetcar began service in and ran along Bowery Street in New York. Stephenson's New York company would become the largest and most famous builder of horse-drawn streetcars. New Orleans became the second American city to offer streetcars in The typical American streetcar was operated by two crew members. One man, a driver, rode up front.
His job was to drive the horse, controlled by a set of reigns. The driver also had a brake handle that he could use to stop the streetcar.
When streetcars got bigger, sometimes two and three horses would be used to haul a single car. The second crew member was the conductor, who rode at the back of the car. His job was to help passengers get on and off the streetcar and to collect their fares. He gave the driver a signal when everyone was on board and it was safe to proceed, pulling on a rope that was attached to a bell that the driver could hear at the other end of the car.
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