Yes - when Machen and his colleagues were 'kicked out' of the PCUS, and when the modernists took over Princeton Seminary, Machen and others (including Van Til) formed a new seminary, Westminster Seminary (in Philadelphia). After Machen's unexpected death shortly thereafter (1936, I believe), Van Til was basically the 'main guy' leading the new school. Both were theologians in the Protestant/Reformed tradition; Van Til focused more on philosophy and apologetics while Machen was primarily a New Testament scholar.