Questions tagged [engineering]

Questions related to the design, development, construction, and use of human-made objects. General tag for mechanical and electric systems, tools, machinery, building design and construction, military engineering, aircraft, and complex system design.

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60 votes
9 answers
24k views

Why are so many metros underground? Isn't that more expensive than an elevated system?

Starting with the London Underground in 1863, why are so many metros/subways built underground (as opposed to en elevated metro)? This requires a lot of digging and excavation, which to me seems a lot ...
DrZ214's user avatar
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13 votes
2 answers
2k views

Why did Chicago and other cities choose an L (elevated metro) when most others chose underground subways?

From my related question, I'm trying to understand the decision-making that went into metro/subway design. Why did Chicago choose an elevated metro system instead of an underground subway? Most other ...
DrZ214's user avatar
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11 votes
1 answer
305 views

When were public roads cleaned electromagnetically?

In the first half of the 20th century, tires were more often punctured, so metal waste on the roadway was a bigger problem. The book "Lorries, Trucks and Vans 1897-1927" features an electromagnetic ...
Aaron Brick's user avatar
  • 27.6k