Glad that the accident wasn't worse and that it was at an off-peak time.
I'm a rather frequent user of the ORD Blue Line too. I sometimes even use the train to get back from the city to the Hilton ORD at 2-4 a.m. [For years, I used to make sure to have a PDF of the Blue Line schedule so that I could take the train back to the airport at those kind of hours.]
Hopefully it won't be too many weeks until they can stop shuttling people from the Rosemont station to the airport and can resume service on the track.