How to edit Width scale with scripts, or is it even possible?

So i want to edit the Width Scale property of a trail with a script:

for i = 1,50 do
    script.Parent.WidthScale = script.Parent.WidthScale + Vector3.new(0.016,0.016,0.016)
    wait(0.01)
end

with this script i get a error saying: Workspace.BloxyCola_Gamer.Trail.TRAIL:2: attempt to perform arithmetic (add) on NumberSequence and Vector3

i tried the vector3 solution but it didnt work, how do i edit width scale if its even possible with a script. or like without 20 lines of code to edit a simple property like you have to do with custom physical properties