Plans to turn the Metra Electric into some sort of rapid transit service come in three different flavors-
1) The
Gray Line, as mentioned by Eric S., was proposed by Mike Payne about twenty years ago; Payne still actively promotes the plan to this day. The Gray Line would use modified Metra Electric Bi-Levels (removing the restroom and the moving of an interior wall or two to make a larger vestibule) running on the Electric Main Line (as far as Kensington/115th Street) and South Chicago Branch every 10-15 minutes, and the Blue Island Branch every 20 minutes (due to that branch's single track). Trains would continue to terminate at Millennium Station. The plan envisions fare integration with the CTA with transfer discounts.
Payne advocates activating the Gray Line over building the CTA Red Line extension.
Image Source -
http://grayline.20m.com
2) The
Gold Line, as mentioned by Sarah Z., takes the Gray Line proposal and reduces its scope. The Gold Line would run on the Electric Main Line to just south of 63rd Street, where it would continue on the South Chicago Branch only. It would not continue south of 63rd on the Main Line or on the Blue Island Branch. Those lines would continue to be serviced as they are now, once every hour on the Main Line south of 63rd during non-rush periods and once every two hours on the Blue Island Branch in non-rush. This plan also suggests CTA fare integration. No recommendation as to rolling stock, very likely running Bi-Levels as they do now. All trains would still terminate at Millennium Station.
Transit Future, backer of the Gold Line, also supports building the CTA Red Line Extension.
Image Source -
http://transitfuture.org
3) The Midwest High Speed Rail Association has incorporated a rapid transit-like component for the Metra Electric into its CrossRail Chicago plan. Called
Metra City, MHSRA takes Payne's Gray Line idea and expands upon it. Metra City would provide trains every 15 minutes on the Main Line to Kensington, the South Chicago Branch, the Blue Island Branch, as well as on NICTD/South Shore trackage to service Altgeld Gardens and the Hegewisch neighborhood.
Unlike the Gray Line and Gold Line proposals, some or most Metra City trains would not terminate at Millennium Station, but instead turn onto the St. Charles Air Line at 16th Street and continue onto a not-as-yet built connector to Union Station's south tracks, stop at Union Station, then continue to O'Hare Airport. All Metra Electric Suburban trains would then bypass most of the stations within city limits, save for a few transfer stations, and terminate at Millennium Station.
Image Source - crossrailchicago.org
As the graphic shows, MHSRA envisions a similar Metra City treatment for the Metra Rock Island Beverly Branch to Blue Island (using DMUs as opposed to the Electric's EMUs) at some point in the future. It is also mentioned that the UP-North and UP-Northwest lines could provide Metra City service, with 15 minute frequencies as well.
There is no definitive position on CTA fare integration, but MHSRA does advocate for a lower fare structure for Metra City as well as better coordination with CTA and Pace (suburban) buses. Rolling stock is not specified, though the Metra City service is represented in the presentation by a single-level EMU, and the vehicles are described as, "lighter, more nimble trains".
MHSRA does not argue for or against the CTA Red Line Extension in its CrossRail Chicago presentation.
For reference sake, I am including a graphic of the Red Line Extension route -
Image Source -
http://transitfuture.org
The Red Line Extension would add 5.3 miles of track, terminating at 130th Street and the Bishop Ford Freeway, in the same general vicinity as the Metra City stop for Altgeld Gardens would be located. Estimated cost for the extension is $2.3 billion.