As of April 3, Metra's Rock Island trains stop at the new 35th Street Station, 1 block from Shimer. The station is a flag stop, so it is necessary to alert the conductor if planning to disembark there. The Rock Island trains terminate at LaSalle Street Station downtown, and serve the southwest suburbs out to Joliet.
[Rock Island Line schedule as of 4/3/2011 (PDF)]
(Shimer is of course already very well-served by the CTA's Red and Green lines, and also advantageously situated within blocks of the Dan Ryan Expressway and Lake Shore Drive.)