It is inevitable, I suppose, that after a train system has been operating for more than 100 years, it is bound to have experienced its share of accidents, wrecks, and mishaps. A number of factors contributed to the likelihood of accidents early on - on-sight signaling, tight headways, fragile wooden cars, mingling "L" cars with cars of other railways [the CNS&M and the CA&E, specifically] - and the likelihood of accidents has decreased markedly in modern times with the use of signaling systems. Still, many accidents have occurred.
Thankfully, the "L" does not have claim to the worst transportation disaster in Chicago (that dubious honor goes to the 1915 Eastland disaster in which 844 were killed when an excursion steamer capsized in the Chicago River) nor the worst train disaster (that happened in 1972 when two Illinois Central commuter trains collided at 27th Street, killing forty-five). But the "L" has had its share.
It is also worth noting that many "L"-related mishaps are not the fault of the CTA or their predecessors at all, but rather Mother Nature. A fair number of crippling problems have resulted from heavy snowfalls and other nature-related mishaps. These are perhaps the most frustrating because it is difficult to be fully prepared for them and impossible to prevent them.
Listed below are those incidents which could truly be called disasters in some way or another (and the term is, of course, high subjective). Each is linked to a page describing the incident, with an additional page listing those mishaps which, while disastrous in their own right, do not warrant a page all their own.
DISCLAIMER: There seems to be a tendency in the United States to want to blow rail accidents out of proportion. For instance, after the Amtrak crash at Bourbannais, a vigorous discussion ensued about how unsafe rail travel is. Nothing could be further from the truth.
The fact of the matter is that, statistically speaking, rail travel is one of the safest modes in the country. In 1990, for instance, there were 326,346 automobile accidents in the Chicago area, resulting in 771 fatalities, only a few less than Chicago's worst transportation disaster (which wasn't even rail-related, see above). That year, there were no major "L" accidents and no resulting fatalities. The fact is, you're safer on the "L" than in a car.
So when you read these accident reports, please don't think the CTA's "L" is not a safe mode of transportation. Remember to take these incidents in the larger context and do not blow them out of proportion. They are presented only for informational and (if you are truly an unsavory individual) entertainment purposes. The CTA's rapid transit system is a very safe, fast, effective mode of travel in the City of Chicago!
Train Accidents | Weather/Natural Disasters