We're diving off-topic, but System One wasn't junked. Big parts of it still survive today.
SystemOne was initially moved off EAL's books and over to Texas Air's along with some aircraft in 1988, and then a year or so later Texas Air sold 50% ownership of it to Ross Perot's EDS for around $250M (a very fair price for the times) in 1989 or 1990. Continental and EDS then sold off the travel agency platform (SOTA) to Amadeus in 1995, and as recently as 2011, Amadeus was still housed in the old SystemOne offices in Doral, FL and I know several dozen originally-SOTA employees who eventually retired from Amadeus during the last 10 years.
The airline specific functions (PNR, inventory control, ticketing, advance seating, departure control) were retained and repackaged as SHARES, still with joint ownership by EDS and Continental. That continues to today -- United has dedicated functionality in a subset of TPF processors called SHARES-A and HP (who absorbed EDS) sells SHARES-B to smaller airlines.
Functionally... SystemOne really wasn't any better than Sabre, Apollo, Deltamatic or PARS for use with rail or hotels.
That's because at the core, they were all the same system, with code packages having been traded/bartered/sold between UA (Apollo), AA (Sabre), EA (SystemOne), and TW/NW (the original owners of PARS) and DL (DATAS II) because they were all on TPF and it was easy to migrate between instances.
I'll have to dumpster dive for specifics, but I know DB and SNCF were working with Sabre at one point early in the 90's. That was about the time that Amtrak was also listed for availability and ticketing in Sabre.
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