The Milwaukee Depot served the Milwaukee Road, Rock Island, Soo Line and other small railroads. It is still standing, and the trainshed is used as an ice rink in the winter. I believe all these lines went to the La Salle street station in Chicago.

Minneapolis-St.Paul (MSP)is one of the codes shared by air and rail. ABQ is also a lot easier to spell than Albuquerque.

Most or all "union stations" were independent companies owned by some or all of the railroads serving the city. They were (and are -- some still exist, like Chicago Union Station Co.) analogues to terminal switching companies like Terminal Railroad Assn. of St. Louis (which also operated St. Louis Union Station, BTW) or the Belt Railway of Chicago (always freight-only).

For example, the controlling partners in Chicago's Union Station were the PRR and the Milwaukee Road. Burlington and others were tenants. In Washington, DC, the Washington Terminal Co. was owned by B&O and PRR. RF&P was a tenant, as was C&O.

On A-Day, Santa Fe accessed the facility as a tennant under provisions of the 1919 Agreement, as did the Norfolk & Western (Wabash commuter, METRA Southwest Service today) when Dearborn Station was finally closed circa 1973 (64 year old memory cells DO fade).

Under Amtrak ownership today and myself having been removed from the industry for almost 25 years, I know not to what the extent the 1919 Agreement remains in force.

An interesting point regarding the operating provisions of the Agreement is that costs were allocated by wheelage. That means a car riding on six wheel trucks bore a greater portion of the cost than did one on four wheel trucks.

I stand corrected. I recall being told at some point that PRR and PFW&C had 25% shares, and for some reason I thought MILW owned the rest.

BTW, Chicago Union Station Co. still exists. I don't know how ownership is now divided; perhaps Amtrak got the PRR/Penn Central 50%, while Metra got the rest -- or maybe BNSF still owns the Q's share.

If I recall correctly, the opening date was 1953. The railroads were NO&NE (Southern), L&N, ICRR, MoPac?, T&P, T&NO (Southern Pacific), L&A (KCS) either 6 or 7. At one time GM&O came into New Orleans on the NO&NE, but not sure whether they still had passenger service at the time NOUPT opened. The reason for the (?) after MoPac is that the MoPac trains came in from Baton Rouge via trackage rights on the ICRR's Y&MV. Upon opening, L&N had the most trains, but ICRR probably carried the most people. Major trains were:
L&N: Crescent, Humming Bird, Pan American, Gulf Wind. They also had a commuter train.
Southern: Southerner, Pelican
ICRR: City of New Orleans, Panama Limited, Louisiane
L&A: Southern Belle
MoPac: don't recall names, but you could get a through sleeper to Los Angeles via ATSF west of Houston.
T&P: had a day train and a night train to Ft. Worth
SPRR: Sunset Limited

All trains terminated there previous to the Amtrak through Sunset Limited.

Do not recall the number of pre-Union Station stations, but think there were at least 4.

Memphis had two "union" stations. Both fronted on Calhoun Avenue two blocks apart, about 1/2 mile south of downtown. At Calhoun and Main was and is Central Station, built around 1916, owned by Illinois Central, tenants Frisco and Rock Island. It was and is an uninspired brick office building for the IC (offices now empty) with the waiting room on the 2nd floor. Very basic. Wood platforms, metal frame wood butterfly sheds, hand throw switches. Had 10 tracks. Always the busier station. Two track left, used by Amtrak. Refurbished recently.

I think the building has been nicely reburbished. The stub tracks (I once boarded during 1962 #6's setout Sleeper parked on them) now afford platform level short-term parking and taxicab stand. I understand that condos are "in the works' for the vacated offices noted.