This morning, I listened to Argent's Greatest: The Singles Collection. I started paying a lot of attention to the Hammond organ in "Tragedy," and I realized that about halfway through the choruses (between "tragedy before your eyes" and "tragedy for every man"), Rod Argent turns his Leslie speaker from the slow rotation to the fast rotation. At the same time, the chord progression moves up to include higher notes, which the increased oscillation of the Leslie helps to intensify.
The version of "Tragedy" on Greatest: The Singles Collection is the single version (as the title of the album would suggest), but the changing speed of the Leslie speaker is also included in the album version (on All Together Now). I haven't listened to the two versions back-to-back, but I think the only difference is a few guitar lines that aren't included in the single version.
