VR-HFX has covered the TriStar systems rather well...while there are very slight differences between models...all generally correct.
As to flight control redundancy...the TriStar has no equal in this regard, designed right in from the begining.
As an example, a TriStar was landed in the middle east with only one half of one hydraulic system quantity remaining..and done by a brand new First Officer, who had very good training.
The dual channel dual autopilots fitted provided superb automatic approach/langings. CAT IIIC capability built in, from the start...by the folks who migrated to Lockheed from the HS Trident team, so I was told. The only thing missing was Smiths stamped on the autopilot control panel.
The Lockheed TriStar was the cream d'la cream of early design wide-body aircraft, IMHO.
Just like the Lockheed 1649A was the epitomy of piston-engine airliner designs. Douglas made more...Boeing made a lot more, Lockheed provided the most technically advanced designs.