I think most would switch the track to save the 3 workers.

However, if a doctor has 3 patients in desperate need of primary organs, I doubt many would condone taking the life of a health person and harvest their organs to save these people.

Perhaps demonstrating a flaw in utilitarianism.

This old philosophical conundrum is one of the issues they are having to look at with regard to fully-automated self-driving cars. If an accident is inevitable, should it be programmed to go for the smallest number of exterior or interior casualties?

Thinking...

Do I know any of them?
Respective apparent ages may influence me.

You are basically posing a moral dilemma given a no win situation do you chose a lesser over a greater evil, do you become a murderer by intent, or a mass murderer by inaction.

In such a situation, and barring no third alternative then yes, I would sacrifice one to save three, and though I would not like it, I would believe myself to have done the correct if not the right thing.

The needs of the many outweigh the needs of the few (Star Trek TOS answer there).

If it was a matter of one worker dying vs all three dying, I'd pull the switch. I'd feel guilty as all get out afterwards, but I'd pull it.

Tough one. I would try to weigh the positive activist potential of any of them first. For instance, if the one guy has leadership potential and a helpful heart, keep him alive. Or if the three dudes are douches...