Should the CTA Build A Perimeter Subway Line?

[emathias]

Originally Posted by linicx

Okay, so you build a new subway under the city. What happens to the subway when the City floods?
I remember passing a bus almost completely underwater in an under-pass during one of those awful storms.

During the 1994 Flood (which was caused by a puncture of one of the old freight tunnels), the subway was partially flooded. IIRC, they partially cleared it by routing the water into the partially-constructed Deep Tunnel project. I'd imagine the current subways and any new subways would also drain into the Deep Tunnel.

[pvande55]

The construction of the subways was at about the same depth as the freight tunnels. This is so even though the tunnels were buried 40 feet below to allow for subways to be built at 20 feet. Yes, the ash cars were used to remove construction debris, but the narrow gauge tracks had to be removed after construction was finished. Yes it was more economical to use streets and alleys because aldermen cost less than prime real estate. Incidentally there are more curves than necessary because it was more economical to swerve the route to take advantage of lower right of way costs. As far as the circle line studies, I just mentioned the way I would like to see it run.

[emathias]

Originally Posted by pvande55

The construction of the subways was at about the same depth as the freight tunnels. This is so even though the tunnels were buried 40 feet below to allow for subways to be built at 20 feet. Yes, the ash cars were used to remove construction debris, but the narrow gauge tracks had to be removed after construction was finished. Yes it was more economical to use streets and alleys because aldermen cost less than prime real estate. Incidentally there are more curves than necessary because it was more economical to swerve the route to take advantage of lower right of way costs. As far as the circle line studies, I just mentioned the way I would like to see it run.

You seem to have a couple things confused.

First, the freight tunnels did use narrow gauge tracks, and these were used to removed debris. But *in addition* there were temporary narrow gauge tracks laid within the subway tunnels for movement of supplies. These were not freight tunnel tracks, but temporary tracks added just for construction purposes. Tracks have been removed from some of the freight tunnels, but removals that happened in the same timeframe as the subway construction were just coincidental, not a requirement.

Second, you still seem to think that the only reason construction of the "L" happened over streets was that "aldermen were cheaper than [private ROW]." And while I'm sure that was true, it is definitely not in the best interest of a city to go around destroying private homes and businesses. It was in the best interest of the city to choose ways of constructing the "L" that was less invasive. Knocking down prime real estate is not only expensive, but it's bad for tax base, it's bad for quality of life of the citizens, it lowers property values due to uncertainty, it removes some of the customers of the future line, and it's just not ideal. Elevated lines in every other city were also built over streets - New York's elevated lines were over streets, for example - and even modern cities typically only build elevated lines over streets. Talking about corruption in the construction of the "L" makes for a fun, romantic story, but it's far from the whole truth about the process and to claim that it is detracts from the complexity and accomplishment of the process.

You presented the Circle Line items as fact. If it's opinion, then you need to use the phrases "I think" or "in my opinion" or "I would like to see" so that people know you're just espousing an opinion and not just making and uninformed proclamation.

RE: Curves - yeah, so what? Of course a private transit company is going to choose the most cost-effective route. Often a curve would have saved them a lot of money, but that's more a financial fact of life than anything else.

[chirack]

Originally Posted by linicx

Okay, so you build a new subway under the city. What happens to the subway when the City floods?
I remember passing a bus almost completely underwater in an under-pass during one of those awful storms.

It is very rare that subways in Chicago flood. They have a very good pump system. The deerborn subway flooded in the 50ies late in construction before the pumps were fully active or at a time when they were off for some reason and they flooded(along with a huge percentage of downtown basements) when an old frieght tunnel under the river was punctured.

[chirack]

Originally Posted by emathias

RE: Curves - yeah, so what? Of course a private transit company is going to choose the most cost-effective route. Often a curve would have saved them a lot of money, but that's more a financial fact of life than anything else.

While I agree with what you said. Curves can become a problem if they lengthen the route too much. Before the subway the met’s northwest branch used to connect to downtown down what is now the paulina connector and the Garfield line(replaced by the congress line sorta) which entered the loop via Wells(or had it’s own sub terminal at Franklin). When they opened the subway they cut like about 15 mins off travel time because of the more direct route downtown.

There are 2nd phase plans to rebuild these tracks for the circle line(i.e. after connecting the pink and orange lines first). They would connect the segment of California thru Damen(all that is left of the old northwest line) back to the Paulina connector. However the prefered method this time would be via subway instead of elevated track.