In ISR 5/2017 (p. 42), we presented the obstacle warning system developed and patented by Dr. Christian Ortner, which is particularly suitable for the reversible aerial tramways used for passenger transportation and materials handling that are a common sight in the Alps. As reported, it offers several advantages: It avoids the need for a separate carrier rope including supports and anchors for the conventional warning balls; it greatly facilitates maintenance, e.g. in the case of color fading, and it eliminates the risk of the carrier rope breaking at a point next to the clamps (and the complete string of balls landing on the ground) due to the fact that the rope is not completely accessible for inspection without being taken down. The visibility marker is tunnel-shaped on section and clamped to the track rope from below so as to permit passage of the carriage. That makes the marker ball easily accessible from the carrier for maintenance purposes.
The long wait for the real-life debut of the product was not only due to the bureaucratic hurdles that have to be taken before the final approvals are issued for any innovative system classified as a safety component. In fact the wind tunnel tests conducted in preparation for CE certification, which also led to the decision to fit a spoiler to the side of the marker to prevent excessive oscillation or even rotation around the track rope, were completed in January 2018, and in June of that year the CE certification process handled by the WPK Austria GmbH Kaprun test center had been completed. Shortly before the permit under ropeway law was issued, however, the operator decided to deregister the system from the list covered by ropeway law and to re-register it as a private industrial installation in order to reduce operating costs. Since the original plans from 1964 had faded in places, and some of them were no longer up to date as several modifications had been made without proper documentation, the process involved a great deal of reverse engineering. But that also had its good points: The visibility markers which were mounted on the windy rope span no. 2 of the materials-handling ropeway from Vilsalpsee (Tannheim, Tyrol) to the Traualpe in spring 2018 were kept under observation for two winters with several storms. The observations confirmed the results of the wind tunnel tests, and the concerns initially expressed by the ropeway authorities were proven to be unfounded. In the meantime the installation has been inspected and approved and is now operating. This means that the innovative obstacle marking system is now available for similar ropeways for which a conventional system would entail very high installation and follow-up costs.