How can I make my train go around tracks smoothly?

Hi, so I have my train which works, but it looks weird when its moving. It has a pause in between the nodes and it doesn't go very smooth.

Video: https://streamable.com/1wbhua

My Code:

local RunService = game:GetService("RunService")

local node = 0

function movemodel(model,start,End,AddBy)
    for i = 0, 0.5, 0.01 do
        if not model.PrimaryPart then break end
        model:SetPrimaryPartCFrame(model.PrimaryPart.CFrame:lerp(start.CFrame, i))
    RunService.Heartbeat:Wait()
    end
end

while true do
    local nextnode = game.Workspace.Nodes:FindFirstChild(node + 1)
    local End = game.Workspace.Nodes:FindFirstChild(node + 2)
    node = node + 1
    movemodel(script.Parent,nextnode,End)
end