def get_abs_axle_location(axle_spacing, start_pt, direction):
    """Calculates the absolute location of the axles wrt the start point."""
    abs_axle_location = []

    loc = start_pt #initialize

    for spacing in axle_spacing:
        if direction == "ltr":
            loc = loc - spacing
        elif direction == "rtl":
            loc = loc + spacing
        abs_axle_location.append(round(loc,3))

    return abs_axle_location