On the subject of battery power - Yes it is possible.  The defunct British company Tri--ang, (now Hornby) made an O guage battery set some years ago called the 'Big Big Train'.  O.K., it was a 'toy'   and O guage but the basic accuracy of its mouldings  was as good as any, and on repaint looked pretty real..  Running on Peco Streamline track it ran several years in my garden very reliably using rechargeable standard U2 and U11 cells.  Being battery-powered made track laying easier because there was no need to solder.  T