Have been tearing down and fixing things since young, have good experience with electronics and mechanics.
"Can you buy replacement black rubber bands for wheels?"に関する回答There are companies that sell large sized rubber bands. Perhaps something from a camping shop? http://www.rubberband.com/about-us/rubber-bands-size-chart
"buy replacement track piece"に関する回答It should be possible to make some straight track pieces from wood. Curved pieces might be a bit more challenging.
"Why is the train not moving"に関する回答I wrote the strip down guide the train I had did not work at all. My two main issues were: 1) the lever controlling the direction had been pushed beyond it's limit. Once I'd taken apart the steering wheel it was possible to get in to change that back. 2) the switch for the power was broken, this was fixed by reversing it around using one of the spare contacts.
"Replacement Charger for old Thomas ride on train and tracks"に関する回答You could always take the battery out and use a car/motorbike charger instead.