I wanted to know what train Twain and Cable were riding on, traveling 
from Springfield to St. Louis. So I thought to find information on the 
train derailment on the bridge going into St. Louis.  Behold, a bit from 
the St. Louis Post-Dispatch:

A SENSATIONAL ACCIDENT.

A Faulty Flange Causes a Train to Jump the Bridge Track.

‘The passengers on the in-bound Chicago and Alton train this morning at 
10 o’clock were treated to a sensation on the eastern approach of the 
bridge, which they will remember for many days. The train, consisting of 
a baggage car, chair car, smoking car and sleeper, was proceeding up the 
approach at the rate of six miles an hour when the cross-over switch 
east of the east abutment was run over. The engine, baggage and smoking 
car crossed the switch in safety, but the chair car struck the frog and 
jumped the track, lodging at an angle of nearly forty-five degrees 
across the track and switch. The passengers in the chair car jumped to 
their feet and were soon crowding each other on to the platform of the 
car, compelling others to step down to the floor of the approach. The 
train was brought to such a sudden halt that the passengers in the other 
cars of the train became almost panic-stricken. As soon as quiet could 
be restored the entrance to the east abutment tower was opened and the 
passengers sent up to foot it over the bridge or wait until the chair 
car was jacked back on the track, which operation consumed over a half 
hour. On examining the switch it was found that it was securely closed, 
and the fact that the engine and two cars passed over the switch frog in 
safety left but one explanation, and that is that a flange on one of the 
wheels of the chair car must have been broken and caught on the frog. A 
thorough investigation of the accident is being made.

St. Louis Post-Dispatch January 9, 1885, page 2

I have a pdf of the clip from Newspapers.com for those interested.

-- 
/Unaffiliated Geographer and Twain aficionado/