Wait rail

[v-rob]

This adds a rail type that will stop the cart when it rolls over it, like the start-stop rail, but the cart will start moving again after a specified amount of time. After placing down this rail (it has white between the wood), a formspec will pop up, and here you can specify the amount of time.

[SmallJoker]

Interesting idea. The concept is OK for me, but there are a few points that would be great to adjust: 1) On-drive-over callbacks: Called when "cart_acceleration" is set and the callback exists. This approach allows registering any kind of new rail. Concept:

local new_vel, new_acc = nodedef.on_cart_driveover(pos, vel, acc, self.object)
local stopped = new_vel and vector.equals(new_vel, vector.new())
update.vel = update.vel or new_vel ~= nil
update.pos = update.pos or stopped
vel = new_vel or vel
acc = new_acc or false
if stopped then
    pos = vector.round(pos)
end

2) Why do you check for if not mesecon then? If there's no mesecons the wait time should also be configurable. 3) Assuming this node isn't placed way too often: Please move the formspec handling into the node definition. send_formspec is not needed since you can embed the current value using ${cart_acceleration}. The formspec will update automatically client-side as soon the metadata is received.