Welding to CFrame Tilting Model

[Awwsoomee (Awws)]

The train in the picture is weldconstrainted to the red part (every part is unanchored). The train slowly tilts as the train turns the bends.

I don’t know why this is happening, here’s the code:

local function Update()
	for i,v in pairs(rightmotors) do
		v.AngularVelocity = vel
	end
	for i,v in pairs(leftmotors) do
		v.AngularVelocity = -vel
	end
	for i,v in pairs(mains) do
		v.Orientation = Vector3.new(v.Orientation.X,v.Orientation.Y,0)
		v.AssemblyLinearVelocity = v.AssemblyLinearVelocity.Unit * vel
		v.AssemblyLinearVelocity = Vector3.new(v.AssemblyLinearVelocity.X,-1,v.AssemblyLinearVelocity.Z)
	end
	for i,v in pairs(cars) do
		TS:Create(v.Build.Main,info,{CFrame = v.Chassis.WheelSetFront.Connector.CFrame:Lerp(v.Chassis.WheelSetBack.Connector.CFrame,0.5)}):Play()
		--v.Build.Main.CFrame = v.Chassis.WheelSetFront.Connector.CFrame:Lerp(v.Chassis.WheelSetBack.Connector.CFrame,0.5)
	end
end

Please help!

[Awwsoomee (Awws)]

Don’t worry I fixed it, Solution:
I was updating the orientation of the wrong parts, which were not the ones the CFrame was being attached to. After rewriting the code slightly it works fine.