According to the FCC's database, the Cumberland (Illinois) County Sheriff's Department is currently licensed to use 155.190. Cumberland County is next door to Effingham County, which contains the town Effingham that you referenced. However, the RadioReference database does not display 155.190 as being currently used by the Cumberland County Sheriff's Department. I'm close enough to Cumberland County that I might be able to pick up a usable signal. I'll put this frequency in my scanner to see if I hear anything.
The Clark County (in Illinois) Sheriff's Department is licensed for and is reportedly actively using 155.190 as a Car-to-Car frequency, but the CCSD is reportedly using a PL tone of 162.2. There is only one county separating Clark County and Effingham County.
155.190 is licensed to other agencies within the state of Illinois, but the two listings that I just gave you are the closest to Effingham. Here are the results of my license search if you want to take a look at them yourself to see if anything sounds familiar:
Site / Frequency Search Results
I hope that this information helps. Happy Scanning!