The Wikipedia article seems quite accurate. Tri-X first appeared as a sheet film. Super-XX (ASA 100) was the preferred high speed film at the time, and it gave better quality pictures in just about all respects. If you really needed speed, you used Super Panchro Press Type B (ASA 250), which was probably no worse. Tri-X was pretty much an orphan. When I first got interested in photography in 1949, I think it had disappeared. Tri-X was reborn in the mid 50s in 35mm and 620. It was a rather grainy film, with a distinctive, vital look. It also could be pushed a stop to a stop and a half with little loss in quality. Tri-X gave birth to the hand held, available light photography movement which flourished in the late 50s and early 60s. I first used the film in 1957. It was not nearly as fine-grained or sharp as Plus-X (and nowhere near Background-X motion picture film, which I used a lot of in that period), but it had its uses and produced pretty nice prints. The film changed a lot (mostly in two well advertised steps) during the mid 1960s. It became a lot finer grained and got a softer look, more like the current film. This newer film was just in time for the press photographers' changeover from 4X5 to 35mm, and they adopted it enthusiastically. It has continued to change and improve over the years, getting even finer grained and sharper. The last significant makeover was just a few years ago. It has become an excellent general purpose film, with sufficiently fine grain and high sharpness to compete against ISO 125 films.