Step 1: Anchor the bottom of the line.
We are told $T$ is at the very bottom, so $T$ sits at the lowest level.
Step 2: Place P just over T.
Since $P$ is directly above $T$, the bottom two, from low to high, are $T$ then $P$.
Step 3: Put S above P.
Because $S$ is above $P$, we now have, going upward, $T, P, S$.
Step 4: Add R above S.
The clue R is above S tells us R sits higher than S, giving $T, P, S, R$ from bottom up.
Step 5: Add Q above R.
Finally Q is above R places Q at the very top, so the full column from bottom to top is $T, P, S, R, Q$.
Step 6: Read off the top person.
The highest name in the stack is $Q$, so $Q$ is at the top.
\[ \boxed{Q} \]