By "original train from Chicago to Miami not going through Atlanta" I am sure Amfleet was just referring to Amtrak.
Before Amtrak there were many routes from Chicago o Miami, and I, being born in Chattanooga, was well aware of them.
The Royal Palm (and New Royal Palm) did sometimes have through sleepr from Chicago to Miami but the bulk of the train went from Detroit and Cincinnati to.Chattanooga, ATL, Fla, alsthrough sleepers from Buffao and Cleveland.
There was a companion train to the Royal Palm known as the Ponce de Leon, but it did not have as much through business.
There were trains known as the Southland and the Flamingo which went Deroit, Cincinnati to Knoxville, Atlanta and Florida.
The bulk of the Chicago- Florida traffic(through Atlanta) was by the interliine trains of the Chicago and Eastern Illinois(from Chicago to Evansville, Ind.) the Louisville and Nashville(from Evansville to Nashvile), the Nashville, Chattanooga and St. Lous(from Nashville to Atlanta) and the Atlantic CoastLine from Atlanta to Jax, and the FEC from Jax to Miami. The top train on this route was known as the Dixie Flagler from 1940 until December 1954. Then it was re-equipped and renamed the Dixieland, and was discontinued in November 1957.
Other, slower trains on that route were the Dixie Flyer, and the Dixie Limited.
Last, but far from least, are two other routes from Chicago to Miami which did NOT go through Atlanta. They were the Illinois Central "CIty of Miami" which went straight down Ilinois(like the CIty of New Orleans)then turned over to BHM ALso the South WInd, a Pennsylvania RR train Chicago, Louisville,Nashville,Montgomery,Jax,Miami.A train called the Seminole ran on the City of Miami route.
The Dixie Flagler(later renamed Dixieland) and the South WInd and the City of Miami were the top streamliners. ALso the New Royal Palm, but again it was not PRIMARILY a Chicago train, but more Detroit, etc.
There was a train called the Kansas City-FLoridaSpecial went KC,Memphis, BHM, ATL, Jax, through sleeper to Miami.
If you go back into the 40's there were more trains on most of the above lines. If anyone really wants details I can provide them
The above are generalizations, in the sense that things can change from one year to the next, some through car services changed a lot, some trains went to one coast of Florida only, some both, and sometimes that sort of thing would change.Also, some equipment would be different in the winter because of many people going south for the warmer climes("snow birds").That often meant a lot more pullmans in the winter, some borrowed from off-line railroads, etc.
So, should anybody need anything really specific about former mid-west Florida serviceI can probably look it up if I don't know it from memory.