I cant edit my post. I try one more time and i get this error (method 2) 
My cost.lua file:
function data()
cost_mod.install()
require “cost_mod”
return {
— per m^3
terrainRaise = 6.0,
terrainLower = 7.0,railroadTrack = 50.0, — per m
railroadHighSpeedTrack = 80.0, — per m
railroadCatenary = 15.0, — per m
railroadSwitch = 5000.0, — per instance
railroadBridge = 10000.0, — per instance
railroadBridgeVol = 11.0, — per m^3
railroadTunnel = 25000.0, — per instance
railroadTunnelLen = 1000.0, — per m— fraction of the road cost
roadBusLane = .1,
roadTramLane = .4,}
end