Security cameras have now been installed on 800 rail cars on Chicago's el system, and officials are crediting them for a drop in crime.
The entire transit system has 23,000 cameras, which are helping police identify suspects in crimes on buses and trains and nearby streets.
Chicago Transit Authority President Forrest Claypool told reporters Wednesday that serious crimes declined 26 percent since Jan. 1. Robberies fell 38 percent and cases of aggravated battery dropped 44 percent compared with a year ago. Thefts were down 23 percent.
In that time, CTA cameras have helped in the arrest of 93 suspects, most of them for robberies and thefts.
Claypool said video images also recently led Chicago police to arrest a suspect in a sexual assault last month in the Wrigleyville neighborhood.