The Effect of Transmission Lines on Railroads

This item is excerpted from an article at T&D World. Read the full article here: www.tdworld.com.

In the electric industry, many workers are familiar with induced voltages and their potential impact on electrical work. Typically, crews are informed about other nearby power sources in the morning job brief, prior to the start of construction. Something not often discussed is that the same concept of voltage being present on supposedly dead conductors also affects railroad signaling, operation and safety.

In the modern era, railroads are moving to much more complicated signaling while still using the rails as the fundamental medium for communications. They have moved away from DC systems and now favor alternating-current (AC) frequencies to transfer their signals. This, in coordination with expansive relays and signaling devices, makes the signals much more susceptible to power line interference, which also is AC. Making the issue even more significant is the frequencies used often approach power line frequencies (60 Hz in the United States) and their harmonics, which makes it much easier for interference to occur.

Because of recent changes in railroad signaling technology, all railroads are becoming more and more susceptible to interference. If not appropriately mitigated, this interference could cause railroads to shut down and even damage their signaling equipment. In many cases, the interference also can make it difficult for the utility to obtain line outages. As the utility continues to use land next to railroads, induction studies should be completed more and more frequently to ensure the two systems can operate in harmony.”


BONUS: Here’s a video of a line being strung across an active railroad track: www.tdworld.com.

“Search Bubble” OR “Filter Bubble”

From wikipedia.org.

“A filter bubble is a state of intellectual isolation[1] that can result from personalized searches when a website algorithm selectively guesses what information a user would like to see based on information about the user, such as location, past click-behavior and search history.[2][3][4] As a result, users become separated from information that disagrees with their viewpoints, effectively isolating them in their own cultural or ideological bubbles.[5]

“The term was coined by Internet activist Eli Pariser circa 2010.”


For more information: www.google.com

Top 4 Sites Like DuckDuckGo

“DuckDuckGo is arguably the most famous private search engine around. However, there are a couple of other ones out there that you can try if DuckDuckGo just doesn’t fit the bill for you. Here are [ . . . ] four recommendations for other search engines like DuckDuckGo.” techboomers.com

A true story based on “the tangled evolution of e-health technology”

“Hospitals, nursing homes, and other medical facilities use a patchwork of methods to track records, and they often aren’t in sync. The collective costs to patients, hospitals, and the economy as a whole are impossible to quantify, although some experts say a cohesive system could save billions.”

This story happens to be centered here in Palo Alto, CA, but it’s told as one that could happen to happen to anyone at any time.  Some of us may even know someone in it. Read it at undark.org.

Found via metafilter.com.