I don't think there are any for CTA and trains run often enough
Here are Metra frequencies, copied from
https://www.radioreference.com/apps/db/?aid=4563
Frequency License Type Tone Alpha Tag Description Mode
160.30500 KNFX766 BM CSQ Metra13 SW 13 Metra SW Service, Chgo to 21st St FMN
160.44000 WNQU573 BM CSQ Metra22 SW 22 Metra SW Service, 21st St to Manhattan FMN
160.77000 KFW518 BM CSQ Metra44 MN 44 Metra Milw Dist North FMN
161.52000 KFW519 BM CSQ Metra94 MW 94 Metra Milw Dist West FMN
161.02500 WNMV660 BM 173.8 PL Metra61 ME 61 Metra Electric FMN
160.92000 KNFX766 BM CSQ Metra54 HC 54 Metra Heritage Corridor FMN
161.34000 KSB864 BM CSQ Metra82 RI 82 Metra Rock Island Dist FMN
160.60500 WNBG753 BM 146.2 PL Metra33 PD 33 Metra Police FMN
161.61000 KFW518 BM CSQ Metra PD Metra Police FMN
453.48750 WPTW445 M 77.0 PL Metra PD MX Metra Police Mobile Extenders FMN
161.22000 WNBG753 BM CSQ Metra74 PasSv 74 Metra Passenger Services FMN
160.63500 WNBG753 BM Metra35 Police 35 Metra Police FMN
150.89000 WQXZ480 RM Metra CUS Metra Union Station FMN
That website has all the frequencies for Illinois railroads