> 5G eh That aint no tinny rocket in my book do the sums for a typical train > of 30 carrages each with 30 000Kg and an engine of 150 000 > Why do you think I want to buy some when the project gets canned :) You'd have to do it per car, of course, if you put all that on the front, the rest would derail. Messy. That's a whole lotta newtons though, even for one car's worth. Actually, you could control the thrust curve fairly well by how the grain is cored. It would be really amusing if the rockets went off with load of pigs instead of a load of steel! That would be "When pigs fly!".. Backwards!