World’s Easiest DIY Electric Train

Hey, great video. This is really applied physics and easy to understand. But what I wonder: Do we really need magnets on both ends of the battery? You showed that the coil itselfs produces a magnetic field once the "circuit" is closed. This magnetic field should be able to push the battery forward, as long as there is "flowing electricity". Would two pieces of round iron (touching the coil) attached to the battery´s ends be enough?
We know that when moving iron towards a magnet it gets attracted. But will a electro-magnetic field be enough to attract iron or do we need a magnet?
To invert the experiment: we could say: World´s simplest power plant. Using a magnetic coil and let a small iron ball run through it. This would induce electricity, right? we just need a "consuming device" at the egde of the coil, like a small lightbulp connected with wires to both the ends of the coil... Would this work ? Greetings and best wishes! Keep on shooting such videos!