Bukkit

What is the issue?
I have a question!

Please provide any additional information below.
When using this sign to create the lift for the rollercoaster:
1:[+Train] / 2: property / 3: speedlimit / 4: 0.04
The train goes onto the hill with no probs (also slowdown set to false),
but how do i let the minecart behave normally again,
so that if i want to create the drop, and use this sign:
1:[+Train] / 2: property / 3: speedlimit / 4: 1
It doesn't immideately go 1, but i want the limit to be 1,
or just to let the minecart behave like it was without the previous signs,
that it can roll down the hill with normal minecraft physics.

Please help,
Kind Regards!