LeapinLarry looking at the Lionel 2133140 UP Genset 2706 manual on page 6, it didn't mention anything if the smoke unit will automatically turnoff at high temperatures. On my First Run Edition Big Boy it has a feature that will automatically turn off at high temperatures to ensure the smoke unit doesn't fail and get damaged. This may be because the same smoke unit on my Big Boy supplies smoke to both the stack and whistle. The Genset while having three stacks only uses one unit.
Next time I come over we can take a look at the Genset! Hope all is well!