The machines were identical, as far as I could tell, apart from small details
Thunderbird 1 only had one oblong porthole window and this was covered by a metal sheild when flying, scot almost fell out of it when he was shot down in the desert.In the old series.
TB2, the wings never folded up but faced forward and the pods where more rounded in shape, there was a different tractor used to pull the pods along as opposed to a static engine in the original,
Thunderbird 3 didnt have any windows,
Tracy island was one island not a series of islands,
The tracy house has been totally rebuilt,
and lots more differences.