Geological conditions were clearly a factor. But another contributing factor was that the elevated lines were owned and operated by one or more private companies from their early 1890s steam-age construction until 1948 (or so).
The City government wanted subways, and had several plans for them from the late 1900s onward. But the City would have had to build subways and then lease the use of the tracks and stations to Chicago Rapid Transit. CRT had no incentive to build subways when it had perfectly good elevated lines. Stated another way, CRT wasn’t asking the City for permission to build new lines, which the City could then insist would be subways. By contrast, the private transit companies in NYC were asking the City for permission to build new lines in 1900-1920 and that City’s gov’t could insist that they be subways.
It’s notable that, despite having official and unofficial (Burnham Plan of 1909) plans for subways for parts of three decades, the City didn’t actually commence construction of subways until the late '30s, when there was federal money available to contribute to the construction costs. The tech for building a subway in wet clay probably caught up by then, but it was still probably too expensive for the City tax base alone to pay for it.
The relative cost for subways vs. above-ground probably depends on whether there was already construction on the ground. If there’s nothing there yet, you can make a tunnel by digging a big ditch and then covering the top, but that’s not an option if you need to go under existing construction.
And the existence of below-ground trains in Chicago does not imply that they’d solved the water table problem: Maybe those were just in higher-elevation parts of the city.
But, seriously, both lines with subways (the Blue and Red Lines) go under the Chicago River, so the subway sections certainly aren’t limited to higher-elevation areas.
Yeah, my recollection is that the names were formalized in 1993, with the opening of the Orange Line. I could swear that in the mid-80s and into the early 90s we called the El to Wrigley Field the Howard Line, not the Red Line. And that even I, as a freshman at NU in 1993, was still used to using the old naming convention rather than the colors. But memory is a funny thing, so I may be wrong about that, although I still find myself using the old names.
According to this, the routes were first color-coded in the system maps in 1985. Also note that the current routes are not the same, particularly the Red and Green Lines.
[continuing the side conversion]
Also, the “Evanston Express” was and is a specific subset of the Purple Line that only runs during rush hours, so if you wanted to tell somebody to take it, you’d have to (and still do) refer to it as the “Evanston Express.” Otherwise, the Purple Line (non-Evanston Express) just stops at Howard, and you have to transfer to the Red Line to get to the Loop.
[/side convo]
Els were quicker and easier to build; New York had them before subways. It was simpler and far cheaper, plus, in the days when all locomotives were steam powered, you didn’t have to worry about ventilation and poisoning your passengers with CO (the one exception in NY, of course, was Alfred Beach’s pneumatic subway, but it didn’t run very long).
New York had Els up until after WWII. By that time, most of the subway system was finished, and the Els were taken down because no one wanted to live or work by the lines. Removing them improved the value of the property.
I’m sure Chicago build Els for the same reason as NY, but no one tried to set up a competing subway system.
It still has them. Most of the elevated line in Manhattan are gone, but the majority of the system as a whole is elevated or above-ground, with some parts that predate even the IRT.
This is true for Manhattan but as has been mentioned not for most of the city. The last El in Manhattan, the Third Avenue El, closed down in 1955 (although it continued in the Bronx until 1973).
Here’s the existing El for the 6 trainat the street I grew up on in the Bronx. I don’t know how people with apartments right next to the line stand the noise.
Don’t remind me. From '91 - '92 I worked downtown and lived in Evanston, but worked Wed-Sunday with my ‘weekend’ on Monday-Tuesday. So on most days I could take the Express all the way to the loop to catch my bus, but on Saturday and Sunday I had to take the interminable Howard line all the way to the end and change to Purple. It was sufficient motivation to finally buy a car (since at least I had free parking at work).
Apparently, the “Evanston Express” is called the “Purple Line Express” these days, so I should make that correction. I only know it as the Evanston Express, though. (Lived there from '93 - '98.)
There are a few hills (and, at least one gentle ridge, which I’ve been told is the remnant of a primordial shoreline of Lake Michigan), but I’d be stunned if there’s any land in the city of Chicago which is more than 100’ above the level of the lake.
When they were building part of the San Diego Trolley through midtown, they did not want the trolley lines to disrupt traffic flow, so they either had to build a bridge or a tunnel for the trolley line. Some people wanted a bridge because it was a lot cheaper than digging a tunnel. Some people wanted a tunnel because a bridge would split the neighborhood with a visual barrier.
The solution was a bridge over Laurel Street with a tunnel a few blocks south at Grape Street. So in the span of just a few blocks, trolley riders go several feet above and below ground. One newspaper dubbed it the great San Diego Roller Coaster.
Chicago’s first L line opened in 1892, when there were not yet any subways in North America. The first two lines used steam locomotives, which were pretty impractical to run through subways. The cost of building subways was astonishing even then, and L lines could be built very rapidly to the World’s Fair of 1893 and to outlying districts and suburbs. By the time the Union Loop was built in 1897 downtown citizens were already starting to be wary of the noise and dirt of the L and asked for subways. The private owners of the L lines managed to head off such demands by means both legal and extralegal.
Chicago’s soil conditions are actually pretty good for subway construction. Most of downtown has a layer of blue clay 40 feet down, which was just carved away by hand (using power knives) and thrown in muck hoppers. Cast-iron rings were bolted in and concrete grout poured behind that. As early as 1863, Chicago tunneled two miles out under the lake to bring in fresher water.
Yes, relative costs of construction is a biggie. I attended a talk once on the construction of BART (San Francisco area commuter train), which is partly above ground, partly below ground, and partly on the ground. It was mentioned that below-ground is BY FAR the most expensive to build, while on-ground is the least expensive.
As Chronos suggests above, it may also depend a lot on what is already built there. In BART’s case, some of the underground parts (particularly in Berkeley) went under fully developed urban territory, at frightful expense. But, they said, that’s the way Berkeley wanted it. (I gathered from that remark that the City of Berkeley actually had to pay for it.)
ETA: I also had a chance to attend an arranged tour of the trans-bay tube, which I think was the last one ever allowed before it opened for business. In between the east-bound and west-bound bores there is a hallway, which they call a “gallery”, about large enough to drive a car through, or nearly so. We walked out a short way into that. There are periodic doorways into the bores. This provides a pedestrian escape route in case trains get stuck down there.
There were once lots of elevated lines in Manhattan. The Second Avenue El, the Third Avenue El, the Sixth, and the Ninth Avenue El. Els were first. Most of the Els were torn down as subways took over. The first torn down were the Ninth and Six due to the Eight Avenue and Sixth Avenue subways.
The Second was torn down in the late 1940s, and the Third Avenue El was the last torn down in the 1950s.
New York used Cut and Cover for most of their subways. They had lower water tables, and firm bedrock which might be why they were able to replace their Els with subways.
Stated another way, CRT wasn’t asking the City for permission to build new lines, which the City could then insist would be subways. By contrast, the private transit companies in NYC were asking the City for permission to build new lines in 1900-1920 and that City’s gov’t could insist that they be subways.
