Ok, so I am building this underground railroad!! No, it's not just for blacks! Well, im going to need like 3000 pieces of railroad, some of them being powered rails ( like 600). I plan on making railstations along the way for people to add to if they want to join up on it. If anyone has extra rails or material to make different rails, I could use some! It would be greatly appreciated!! Thanks!

1 powered rail per 28 regular is the optimal speed vs conservation.

I thought you needed more powered rails if you plan on using storage carts

If a person isn't in a minecart, the minecart slows down a lot sooner than with a person inside it. This may be so that the cart doesn't fly away, though it's still possible if there's enough powered rails. If a storage cart reacts in a similar manner in regards to a minecart with no person in it, then yes more powered rails will be needed. I've yet to test this out myself or read up on it. Might just start a random creative world and give it a try. Also, I hate that the whole fast forward and rewind thing was removed from the creative mode when the update was released as it makes testing like this a pain in the ass. Of course there's always single player commands but then there's no point in having creative mode... well, almost no point.

Just did a little testing with storage carts. If you have a 2 block high button starter as we normally do and use 2 powered rails with that, the cart will go about 8 to maybe 10 blocks, slowing down around block 6 or 7. If you do 8 rail then 2 powered rail after the start, that seems to work pretty well. If you don't want to use as much powered rail, I would say 7 rail before the next powered rail is the max. If you do 8 rail and then 1 powered rail, it will go for a while but it slows down gradually. I only did this for about 60+ blocks and though the storage cart can get to the next powered rail even as it's slowing down, I know that there is unknown factors that could bring the cart to a halt when it's going over a long track like what you're planning on making. It'd probably be good to do some testing as the rail is being made, but this is a good bit to keep in mind while making it.