69 votes

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

In Moscow, under former mayor Yuriy Luzhkov, it was built a line (Butovo line) which is mostly elevated. I think the practice was not considered quite successful as a result. There are many drawbacks: ...
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58 votes

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

This is mostly about urban planning, and how much change the local government can or will be able to make to the existing streets. In London, the central parts of the city (Westminster and the City) ...
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46 votes

Did ancient peoples ever hide their treasure behind puzzles?

One man's lock is another man's puzzle. Combination locks have been used since at least ancient Rome. Whether the lock uses numbers or letters (or other symbols), the combination to be entered may be ...
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42 votes

Did ancient peoples ever hide their treasure behind puzzles?

The Copper Scroll The Copper Scroll is a Dead Sea scroll found in 1952, unique in that it is of copper (with a little tin), has a list of 63 or 64 locations of treasure with "obscure hints of the ...
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40 votes
Accepted

Why did Jodrell Bank assist the Soviet Union to collect data from their spacecraft in the mid 1960's?

SHORT ANSWER Jodrell Bank's first 'coup', tracking Sputnik 1 in 1957 (without Soviet assistance), put it in the news and helped secure funding. It also led to a congratulatory telegram from the ...
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37 votes
Accepted

Are steam engines still in regular use anywhere in the world?

There are plenty of industrial uses for steam engines, mostly for generating electricity. Any coal-fueled power station is a steam engine, or more likely a set of them. The only big change in ...
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  • 3,294
31 votes

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

For New York, the answer is related to real estate value. In New York City, the construction of the metro was performed by real estate developers. The idea was to build homes, then connect them to ...
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28 votes

Are steam engines still in regular use anywhere in the world?

Nuclear power stations are steam engines, they just use a different source of energy to generate the steam from what you're probably thinking of. So yes, steam engines are in widespread use around the ...
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22 votes
Accepted

What were Greek and Roman sails made from?

Ancient Mediterranean sailcloth was made of a fine linen, which was written "linon" in Greek and "lintea" in Latin. Many ancient literary sources mention this, for example, Aeschylus, Virgil, Homer, ...
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13 votes

In what year did Charles Proteus Steinmetz fix Ford's Generator for the famed $10,000 invoice?

It would have been somewhere between 1917 and 1923, and thus the amount on that check would be the rough equivalent of getting a check for $150k-$200k today. Assuming the story is true at all, of ...
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12 votes
Accepted

Would every Roman army have dedicated engineers?

As the comment above indicates, the Roman army before Julius Caesar's time seems to have had a dedicated engineer corps, but this group would also be expected to fight if necessary. From Julius ...
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12 votes

Are steam engines still in regular use anywhere in the world?

Steam Engine: A steam engine is a heat engine that performs mechanical work using steam as its working fluid. Unless you are specifically referring to steam railway locomotives, a particular ...
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11 votes
Accepted

How long did it take to build earth dikes with low-tech tools?

Julius Caesar is alleged to have completed a 25 mile double circumvallation (11 miles inner, 14 miles outer) of Alesia in 30 days, with approximately 50,000 men - though at all times, of course, some ...
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11 votes

How long did it take a typical capital warship to ramp up to flank speed?

The answer to that is difficult. It has to do mainly with technological limitations and fluid dynamics. In fact, you should ask about time to flank speed, as this would be your only measure of maximum ...
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10 votes

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

I don't know about other cities, but Chicago appears to have had many troubles with its underground terrain, to the point that, to build their sewer system (once these things became "fashionable" :-)),...
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10 votes

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

Noise, vibrations, and visual impact drop the value of the nearest houses, and decrease quality of life for its inhabitants. The maintenance of an elevated system is expensive, not only economically ...
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9 votes

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

Quite often subway lines are built to relieve traffic pressure on areas where there is no room to add more roads, including the towers needed to allow for the creation of elevated roads or railways. ...
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  • 10.9k
9 votes

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

Based on my knowledge of geology, adding to @sjuan76's answer: The geological map linked by Sjuan76 shows that most of the area underneath Chicago city is, as he says, beach ridges, sands, and gravel....
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8 votes
Accepted

When were public roads cleaned electromagnetically?

Well, the truck was definitely real, not an artists concept sketch. An image gallery at the Nevada Department of Transportation website shows the following picture: The caption simply labels it as an ...
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8 votes

Where is (or was) the biggest medieval drawbridge?

The purpose of the drawbridge was to deny access to the castle gate. As such, spanning large distances was not usually necessary, at least by the drawbridge itself. The still-operational drawbridges ...
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8 votes

Why did the steam locomotive take so long?

The steam engine was invented around the start of the 1700s Thomas Newcomen's 1712 atmospheric engine — itself an improvement on Thomas Savery's 1698 steam powered pump, known for being prone to ...
7 votes

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

I can add that Washington DC is still expanding its Metro and the expansion is not underground. The newest line is the Silver Line, and as it goes through Tysons Corner it's almost entirely elevated. ...
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6 votes

Are steam engines still in regular use anywhere in the world?

To my knowledge, there is one single cylinder steam engine at the Hook Norton Brewery in England, still working for it's living, and there are several Steam Boats around, such as the Paddle Wheeler ...
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6 votes

How close did the French come to digging a canal across the Isthmus of Kra in the 1880s?

tl; dr How close did the French actually come to succeeding at getting the project underway? The project never came close to getting underway. The route chosen for the survey proved to be ...
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6 votes

Why did the steam locomotive take so long?

As the adage goes, necessity is the mother of invention. If there isn't a perceived idea, it doesn't get invented. Things get designed to solve a particular problem. There is also the issue of the ...
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5 votes

How advanced were the people of Indus valley civilization in engineering?

It would be hard to compare with other contemporary civilisation at the time viz Egyptian or Sumerian as not much written information available of that time. However, archealogical finding suggests ...
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5 votes

Why did the USSR switch from 1524 mm gauge to 1520 mm gauge in the late 1960's?

This was done to improve stability of the existing rolling stock. If they just changed the tolerances, they would need both new stock and new rails for the benefits to have force. With changing the ...
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5 votes

Why did the USSR switch from 1524 mm gauge to 1520 mm gauge in the late 1960's?

The Wikipedia article you refer to gives a reference which says that this change "increased speed and stability". Which can be explained, of course. Suppose you have two gauges, 1524 and 1520 with the ...
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5 votes

Are steam engines still in regular use anywhere in the world?

A large variety of preserved and rebuilt steam locomotives are still used on well over a hundred heritage railways in the UK, some well over 10 miles in length. See the list of British Heritage and ...
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