An Amtrak train entered into the back of a freight train on Friday leaving five people in critical conditions and others with minor injuries.
Nine people were reported to be in serious condition and another 30 received bumbs and bruises treatment.
The number is expected to rise to 50, said Raymond Orozco, Fire Commissioner.
The Amtrak's three double-decker passenger cars didn't receive serious damages and most of the 187 passengers walked away without serious damages.
The Portion of the Norfolk Southern freight train that was struck had no occupant, and other two workers on the train remained unhurt.
Four people had to be extricated from the front of the train, said Orozco.
Rescue workers at the scene helped the Amtrak passengers to get off the train on the city's South Side although some had to be taken away on stretchers and backboards.