If I'm thinking right, some doubt about that, with the coil connected (closed loop), it would appear to me that the long coil's magnet polarity would offer some opposition to the battery "train" movement rather than reinforced it.
And than again, I could be totally off track :)
Right, that’s what I said in post 28: that I realized I was wrong in post 18 when I said that the long coil would reinforce the action of the short coil.