My Kato S14701 TGV arrived in pretty good condition, but still needed a bit of TLC before it would run. It dates from the 1980s and the wheels looked like they haven't ever been cleaned, but apart from that, all the paint is still in tact, nothing is missing, etc, so I think I did pretty well. However that said, if I wanted it to move at all, it would need a DCC decoder.Disassembling
First trick is to dismantle the power car. The only outward clue is a small screw on the nose which must be removed:
(Yes I know the wheels are clean here, I cheated and took this photo at the end!)
Then one needs to gently prise the body away from the shell. Do this front and back around each set of bogies.