IBM SSEC, which has started operation at the beginning of 1948, has been for a few years the fastest and most versatile computer in the world (unlike the special-purpose ENIAC) and it has solved a great number of important problems of scientific and technological interest.
It was a hybrid electronic-relay computer, containing more than twenty thousand electromechanical relays and more than ten thousand vacuum tubes.
This is likely the biggest and most complex relay computer ever made, though its main arithmetic part and its fastest registers were made with vacuum tubes, for increased speed in comparison with a pure relay computer.
Thanks!
The Enigma-cracking Bombe (on display at the extraordinary Bletchley Museum of Computing) also used relays
https://www.tnmoc.org/bh-10-bombe-description
And the Z3 as well!
https://en.wikipedia.org/wiki/Z3_(computer)
IBM SSEC, which has started operation at the beginning of 1948, has been for a few years the fastest and most versatile computer in the world (unlike the special-purpose ENIAC) and it has solved a great number of important problems of scientific and technological interest.
It was a hybrid electronic-relay computer, containing more than twenty thousand electromechanical relays and more than ten thousand vacuum tubes.
This is likely the biggest and most complex relay computer ever made, though its main arithmetic part and its fastest registers were made with vacuum tubes, for increased speed in comparison with a pure relay computer.
https://en.wikipedia.org/wiki/IBM_SSEC