Why do train conductors have their heads out?

Why do Japanese train conductors stick their heads outside the window when the train is departing the platform? Is it to alert the engineer / driver if there is some safety problem?

Yes, they check that the departure is safe. They press an emergency button in case something is wrong, e.g. somebody or something is stuck in a door or somebody falls onto the train.

They must stop the train immediately when passengers on the platform "touch" the running cars accidentally. There are so many passengers on the platform during rush hour.

They also need to breathe some fresh air..

Well, to be precise, they stick their heads out so that they can see with their own eyes, without relying on monitors or mirrors, that every edge of the train and platform are kept safe.

If there is a problem and they need to contact the driver, they pull their heads back in and use a sort of an interphone.

Generally speaking, in Japan "mokushi" in other words "visual confirmation with own eyes" is respected even when driving automobiles or walking as a pedestrian.

Seems like many of them also have "モテキ". (haha, couldn't resist saying that)

Thanks for the answers, everyone. So mokushi it is.

Mokushi is 目視, visual confirmation.
Don't make fun of it. It is a serious business for the safety of the passengers & users. People die if they drop the ball. That's why Japan trains are the safest in the world & on time. Have you seen them on duty talking on a cell phone, influenced by drugs, putting legs up on the dashboard, etc. like in US? They, passengers and others are injured or dead everyday.
Observe all the hand gestures of conductors, drivers, station staff, etc. every train, everyday.

@amazinga Sorry if I offended you with my "モテキ" comment. That said, lighten up. There are many differences in attitude between Japan and the US. For example, there is not trash everywhere in Japan, the crosswalk signals work and people wait for them, etc. I am not making fun of 車掌 -- just noting that many are young and attractve.

Have you never put head out the window of a moving car...feels amazing.
No all joking aside, the drivers don't do drugs like in foreign countries...they do however work in constant fear of serious reprimands like fines and humiliating retraining. Japan's most serious train crash in recent history was in 2005 when 106 passengers and the driver were killed. According to the crash investigation it was thought the fear of these reprimands may have caused the driver to speed up to make up for a 90 second delay.