Quote:
Originally Posted by ardecila
It's only possible to grade-separate Clark Junction if they drop the outer tracks between the junction and Addison (which is fine if Purple runs express in the center tracks to Belmont/Fullerton). Otherwise the viaduct would need to grow to a six-track width for several hundred feet, requiring additional property.
|
If the subway is built, all of the elevated immediately north of Belmont would disappear except for the Brown Line tracks. The Purple Line express would essentially disappear.
Quote:
Originally Posted by ardecila
Not a bad point. However, there's most likely a massive rats-nest of utilities under Sheffield that would probably need to move to make way for the subway station. All that utility work is pretty expensive, so if the station can be built under the alley instead, it might save money overall. If the eventual plan is to replace the line with a 2-track subway, then it's pretty easy to rip down two of the elevated tracks and start building the underground tracks right there.
|
Why would you spend $4 billion on a new subway and cripple it by saving, proportionally, nickels and dimes on a single station? There will be a lot of utilities under all the proposed stations - that's just part of the cost of building the subway, and doing it right, instead of nickel and diming away the key benefits of a subway would be not just silly but outright stupid.
It would not be "easy" to just rip down two tracks and start building a subway station. You also seem to be under the mistaken impression that there wouldn't be any utilities under Addison and the alleys around the existing Addison station. On that block, just about anywhere you build would have utilities under it. Again, why save pennies and reduce the quality of the end product?
Quote:
Originally Posted by ardecila
I'll leave it up to the engineers to figure something out... I'm sure whatever they choose will be some awful penny-wise pound-foolish plan, so there's really no point in us debating it.
|
It will definitely be penny-wise, pound foolish if they do any of the things you've suggested.
Quote:
Originally Posted by ardecila
If you have a chance, read Cecil Adams' recent post about the RPM project... apparently the consultants are operating in a complete vacuum with regards to the system-wide consequences of each alternative. I'm sure some consultant was sitting there figuring out the cost of a 4-track elevated and sarcastically remarked that the cost was approaching that of a new subway, and *tada* a new alternative was born.
|
I like Cecil and all, but he's prone to his own mistakes in judgment and knowledge. He actually published a letter I wrote him where I corrected a significant flaw in one of his articles years ago.
For one thing, in his commentary on the LA's transit, he starts off citing the Texas Transportation Institute's studies, which are widely criticized for their inappropriate and often irrelevant methodology.
In his RPM commentary, he dismisses operational coordination concerns rather flippantly, with "In theory this shouldn't be difficult," when, in fact, theory would tell him that it IS difficult. You have trains that are reliant on people boarding quickly and efficiently, and it only takes a couple people holding the doors for their friends to screw up coordination. Or a slow zone, something that is impossible to completely prevent on 24-hour service lines like the Red Line.
If the CTA chooses to rebuild the existing elevated, the CTA has said they're likely to do something similar to what Cecil proposes. They have, in other plans, talked of routing the Purple Line through the subway - in fact, that was part of the Circle Line proposal.
Cecil doesn't directly address the subway alternative, or consider how it could be run. He chooses to ignore that the subway would result in faster service than current operations for nearly everyone due to a combination of more frequent trains, reduced number of stations, and higher speeds on tracks that will experience less-frequent slow zones because of their straightness and protection from the elements.
He comparing existing infrastructure to only one of the CTA's alternatives, not even considering all of the alternatives. That makes it a little hard to know how to apply his commentary to this discussion.
Prev
Seconded, especially the part about the location of the Addison station. From what I’ve read there wouldn’t be much of a difference between the current Evanston Express and the all-stops tunneled alternative largely because of platform consolidation and strategic station placement. That, combined with higher potential ridership (from shorter headways—wait times add significantly to perceived travel time—and faster urban service), an increased number of entrances, lower long-term maintenance costs (shielded from the whether, fewer tracks), and getting rid of the flat junction at Clark have made me a convert to the the two-track underground option. The only things I’d change would be moving the second Wilson entrance north with portals closer to the Broadway/Racine/Lawrence intersection, keeping South Boulevard to retain access to the medical complex on Ridge and dense southeastern Evanston, changing Noyes-Gaffield into Foster-Simpson, maybe keeping the four-track embankment with a minimally-updated Jarvis north of Lunt for Howard trains to stop and Linden trains to skip.
Linear Mode
