What happens if I let the train explode in Chapter 2 Act 4?
Solution 1:
Disappointingly, the train will not explode if the timer runs out.
I ended up testing this out myself. I pulled the train’s self-destruct switch and waited two minutes for the countdown to run out.
When the timer hits 0, Hat Kid loses all her health and dies, as if hit by an enemy. The counter is reset back to two minutes, and you respawn at the start of the level.