local ambientVehicles = {}

local function rebuildAmbientList()
    ambientVehicles = {}
    for _, veh in ipairs(getElementsByType("vehicle", root, true)) do
        if getElementData(veh, "mtrp:ambientTrain") then
            table.insert(ambientVehicles, veh)
        end
    end
end

local function applyAmbientCollisions()
    rebuildAmbientList()
    for i = 1, #ambientVehicles do
        local a = ambientVehicles[i]
        if isElement(a) then
            for j = i + 1, #ambientVehicles do
                local b = ambientVehicles[j]
                if isElement(b) then
                    setElementCollidableWith(a, b, false)
                end
            end
        end
    end
end

addEventHandler("onClientResourceStart", resourceRoot, function()
    setTimer(applyAmbientCollisions, 3000, 0)
    setTimer(applyAmbientCollisions, 1000, 1)
end)

addEventHandler("onClientElementStreamIn", root, function()
    if getElementType(source) == "vehicle" and getElementData(source, "mtrp:ambientTrain") then
        setTimer(applyAmbientCollisions, 300, 1)
    end
end)