const PartSeq &get_parts() const { return parts; }
const EndpointSeq &get_endpoints() const { return endpoints; }
const Endpoint *get_endpoint_by_link(Track *) const;
const PartSeq &get_parts() const { return parts; }
const EndpointSeq &get_endpoints() const { return endpoints; }
const Endpoint *get_endpoint_by_link(Track *) const;