I'm not sure they are yellow in the advert, just discoloured with rust. In the clip above, go to 25 secs, then look at the right hand side.
And yeah, I can't imagine them using different coasters for on and off-ride either.
Oh, and just seen the stickers on the car at 23 secs, so am now convinced it is the Rainbow's End one afterall. Well done people
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)