"Wisdom begins in wonder" – Socrates
Category: Urban Systems
Trolley Poles
09/06/24
“How can we transfer electricity from overhead wires to traction motors using cylindrical poles?”
Current collectors come in all shapes and sizes. Trolley poles are cylindrically shaped poles that bring electricity from overhead wires to power traction motors on trams and trains. Trolley poles were popular with earlier trams but have become less popular as more efficient current collectors have taken root.
Image credit https://upload.wikimedia.org/
Public Water Systems
09/05/24
“How does the US define utilities and organizations that provide drinking water?”
Organizations such as utilities provide drinking water to the public. These entities are categorized as Public Water Systems by the United States Federal Government. The US specifically defines water systems as organizations that provide “water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days a year.”.
Drainage Divides
09/02/24
“What divides two different water basins from each other?”
Drainage Basins are areas that drain into a single point. These are separated by Drainage Divides, or the boundaries of drainage basins. Drainage divides are usually marked by the peaks of mountains.
Human Impact on Sedimentation
08/31/24
“How can humans have an impact on sedimentation?”
Sedimentation occurs with the presence of sediments. Human activity such as dam creation or infrastructure construction can disrupt the environment by increasing the amount of sediment in the water.
Multiple-Unit Trains
08/30/24
“What happens when there are multiple train units connected to one another?”
Trains come in all shapes and sizes. Some have multiple carriages connected one after another. These are known as Multiple-Unit Trains and comprise a large portion of trains in operation today.
Heritage Streetcars
08/29/24
“Why do cities have heritage streetcars?”
Streetcars were historically a very popular form of urban transportation. However, with the arrival of the automobile and the introduction of more advanced trams, their popularity fell. Some cities have taken to preserving specific lines through Heritage Streetcars. Heritage streetcars can be seen in cities all over the world, from Nagasaki to San Francisco to Amsterdam.
Current Collectors
08/28/24
“How is electricity for electrified rail systems transferred from supply to machinery?”
Electrified rail systems, whether they be high-speed locomotives or simple trams, need electric current to power their operations. This is typically done through a current collector, where a device transfers electric current from supply sources to the rail car.
Septic Tanks
08/24/24
“How do septic tanks work?”
Wastewater needs to be purified before it reaches groundwater supplies again. However, many water purification techniques use electricity to work. How can we accomplish this without electricity? Well, what if we were to flush wastewater into an underground tank. The heavy solid contaminants in the wastewater would sink to the bottom, and lighter ones would float to the top and form a scum layer. Over the span of one to two days, the solids should break down into scum. Now what if this tank were to have bacteria that breaks down the solid waste? When the tank fills up more, the liquid will empty into the drainfield and become absorbed by the soil. The bacteria in the soil layers will cleanse the water of contaminants, and eventually transfer it to the groundwater layer. These machines called Septic Tanks are a real thing and this is how they work.
Image credit https://assets-global.website-files.com/
Sewage
08/22/24
“What is sewage?”
Wastewater can contain all types of pollutants. Wastewater that specifically carries human waste (feces and/or urine) is known as Sewage. Sewage is a public health hazard and must be stored and treated away from people.
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