You need to firstly remove the ends of the coaches, they pop out quite easily, then you have to slide something along both sides of the coaches at the same time, business parts are useful for this, start in the middle, you can usually get the card between the roof and the bodyside in the centre of the vehicle. You need to be able to prise the side of the body our far enough to clear the moulded raised windows - the roof and windows are part of the same moulding - and once you have the side far enough out then slide the business card in to hold it. Repeat on the other side with a second card, then once you have both cards in place you can work them up to one end of the coach, whereupon the roof should pop up a bit at that end with a little friendly persuasion... once you've got one end released then you can work your way back to the other end. As the roof comes up it will stop the windows popping back into place and you should be able to remove the roof... once you get into the swing of doing it that will make sense!

Andi