For the train one, I hold that action or inaction are interchangeable, so you should act to minimze the deaths. You're able to push the button or not push the button, the difference is semantic. If you do nothing, you're still choosing. And since the choice is yours, the responsibility for the outcome is yours. Having a brain fart and refusing to choose is still a choice, but it's attempting to absolve onself by blaming "fate".
Some might contend that it's not your place to "choose" who dies, so you're not liable for the 40 people dying, and should let the train hit them so that you didn't actively murder the one person. But I don't think this is convincing. Consider the scenario where the train is hurtling towards 40 people and there is no-one on the other line. If you let the train hit them and go "it wasn't my fault" nobody is buying that. You alone had the power to save them, it is your responsibility that they died no matter how you throw your hands up and claim that you "didn't do anything". Not pulling the lever is ethically no different than pulling the lever when the train was aimed the other way.
I think that regardless of how you measure the worth of human life, it's clear that 40 individuals are worth "more" than one individual, and that them being hit by the train is worse in every way.
To make stakes a bit higher, you can ask, what if the one person on the tracks is your husband/wife, son/daughter or similar.