Late this week the Chicago Plan Commission is expected to vote on whether to allow the new owners of the Aon Center to clamp a glass elevator to the northwest corner of the city’s third-tallest building and put a thrill ride on the roof. If you’re not into that whole “waiting for stuff to happen” thing, here are some tea leaves for you to read:

It’s gonna happen.

How can we prognosticate in such an affirmative fashion? Because of an e-mail that 42nd Ward Alderman Brendan Reilly sent out to his constituents. In the transmission, the downtown pol spells out the concessions that he got from 601W Companies, presumably to win his support. Because, why else would they do it? Not because they’ve got too much money and don’t know where to spend it.

With Mr. Reilly backing the project, that virtually guarantees that the Plan Commission will go along with it. And then the full city council will go along with it because of the tradition that the other 49 aldermen always go along with whatever the alderman for the location in question wants. It’s a custom that exists somewhere in the spectrum between “local alderman knows what’s best for his ward” and “never start a land war in Asia.”

So what are the spiffs that the Don of Downtown got from the Neighbors from New York? A lot of it is the usual things that Reilly asks for: Better sidewalks, new planters, high-visibility crosswalks. All things the city should have built years ago to serve its taxpayers, but this way they get done for free.

There are a few standouts, though:

Taxi, rideshare, school bus, tour bus loading zones.

The elevator shaft will no longer be illuminated, and the elevator cab can’t emit more light than the average Aon Center window.

If the city decides to landmark the Aon enter, the owners have to go along with it.

The Plan Commission meets on Thursday, December 20th. After that, it goes to the Zoning committee in mid-January, then on to a vote before the full city council on January 23. Until then, enjoy the following plethora of renderings and diagrams. We put the renderings at the top because life’s too short to look at diagrams first.