In-Depth

Automated to the Rhine Falls on Route 12

  22.10.2019

The Rhine Falls near Schaffhausen in Switzerland have one more attraction: in June 2019, the route of line 12 was extended. Since then, the new self-driving bus "Trapizia" has been running daily according to timetable from the centre of Neuhausen am Rheinfall down to the Rhine Falls basin and back.

If you travel to the Rhine Falls by public transport, you'd take the train to Schaffhausen and from there the city bus line 1 to the bus stop Zentrum in Neuhausen. The last kilometer is covered on foot. To get back to the bus, you have to climb 55 meters on the way back.

The Laufengasse is particularly strenuous, with a steepness of first 12% and then 15%. For wheelchair users, but also for people who are no longer very well on foot, access to the Rhine Falls is difficult.

S-Bahn stop Neuhausen Rhine Falls with lift
Since the timetable change in 2015, the S-Bahn Zurich-Schaffhausen has been serving a newly equipped railway station directly above the Rhine Falls every half hour. From this station, a newly constructed lift system overcomes the upper level of the Laufengasse and takes you to the Rhine Falls and back again.

Even if the lift system now bridges the upper ramp, there are still 14 meters of difference in altitude to be overcome from the Rhine Falls basin to the lower lift with a gradient of 12%.

Seamless travel chain
In order to ensure convenient access to the Rhine Falls for all visitors, the Schaffhausen Transport Authority has set up the new line 12 and operates it with a self-driving shuttle.

At the Neuhausen Zentrum (north) stop, the shuttle picks up passengers arriving from Schaffhausen by city bus and transports them on a route of around one kilometer to the Schlössli (castle) Wörth on the Rhine Falls basin.

An intermediate stop at the lower lift makes the trip to the Rhine Falls barrier-free, even for rail passengers. If there is a large number of visitors along the Rhine Falls basin, the route can be shortened at the stop of the same name.

From Schlössli Wörth, visitors can take excursion boats to the Rhine Falls Rock, or change to the opposite bank of the Rhine to admire the Rhine Falls from a different perspective, or continue their journey by train to Winterthur. In addition, scheduled boats run down the Rhine, so it is not wrong to notice that line 12 closes a gap in the public transport offer around the Rhine Falls.

Challenge with the gradient
When the vehicle was set up for the described route in December 2016, it turned out that the vehicle could not cope with the gradients along the running track in continuous operation. The engine power was sufficient, but the waste heat could not be dissipated quickly enough.

The vehicle manufacturer promised a remedy with a further developed vehicle with double motorisation and four-wheel drive. At that time, however, this new model was only available on the drawing board.

Pilot operation on the upper section
The Schaffhausen transport authority decided to start a pilot operation anyway. From March 2018, "Trapizio", the 2x4 vehicle, was therefore operating on the upper section between the city centre and the industrial site. With a great response, as it turned out: In the first 15 months, more than 30,000 passengers made use of the opportunity to test the new mobility offering, even if the actual benefit within a travel chain was not yet great.

The test drivers included numerous experts, including board members and department heads of various transport companies from German-speaking countries and beyond, who learned how self-driving vehicles can be integrated into the operations control system supplied by Trapeze.

Replacing the vehicle
After about a year of development, "Trapizia", the new 4x4 vehicle, was delivered at the end of March 2019. The changes were not only constructive in nature: Because of the greater traction generated by two engines and four driven wheels, the software responsible for driving dynamics had to be adapted to the vehicle.

AMoTech was again responsible for obtaining road approval. Only two months later, the number plates could be attached after the vehicle had been individually approved by the Federal Offices for Roads and Traffic.

Bi-directional operation
At the Industrieplatz, the vehicle makes use of its manoeuvrability, made possible by two steered axles and drives a 180° curve. From there, the vehicle continues its travel after a "head change", in which the front and rear of the vehicle are exchanged fully electronically.

This means that all lights, including license plate lighting, are doubled and are switched on or off depending on the direction of travel. The panels, which are normally attached to the rear, are displayed on indicators and can therefore also be switched electronically.

The Swiss authorities require that this head change only takes place in automatic mode. When reversing manually, the reversing lamp must be switched on, as on any regular road vehicle. The vehicle software had to be specially adapted for these subtleties.

The advantages of bi-directional operation are obvious on the route at the Rhine Falls: the doors are always on the same side (towards the Rhine Falls), so that the exact same stop location can be used at each stop, in both directions of travel. The premature turning at the Rheinfallbecken stop is also much easier than if the direction had to be changed several times by driving forwards and backwards.

Integration into the Trapeze operations control system
Even if the shuttle is already visible in the control center and is displayed on the passenger information signs at the stops, integration into the Trapeze control system is still being driven forward. Work is currently underway to control the vehicle so that it keeps to the timetable and always closes the doors at the right time and travels to the next stop, from the depot exit in the morning to the entry in the evening.

AMoTech cooperates with all relevant vehicle manufacturers to integrate their vehicles into the control system. In the longer term, not only the Trapeze control systems are to be supported, but also those of other system suppliers.

Narrow point at the Rhine Falls basin
Along the promenade at the Rhine Falls Basin there are various narrow passages where it is difficult to get ahead amidst the visitors of the Rhine Falls, and it is impossible to cross with other vehicles. Therefore, when setting up the route, care was taken to ensure that other vehicles could pass the shuttle at least at the stopping points.

How a self-driving vehicle can move forward on such a route is part of the experiment. It is clear that a permanent stop-and-go would be very tiring for a human driver. An automated vehicle never gets tired. It is just as attentive at the end of an operating day as it was at the beginning.

Programming the route
In preparation for programming, the route was scanned at night using a 3D LIDARs (laser scanners). From these scans, a reference map was created. On its basis, the vehicle can determine its location with centimeter precision by comparing the environment effectively seen by its LIDARs with the reference map.

The precise trajectory to follow is determined on the basis of the LIDAR map. For each route section, not only the driving speed is programmed, but also the lateral safety distance and other parameters.

Moving forward in a narrow pedestrian passage is not without its advantages for a self-driving vehicle. The programmed speed along the Rhine Falls Basin is only around 5 km/h. The speed of the vehicle can be adjusted by the driver. At this low speed, pedestrians do not step far to the side when they make room for the vehicle. This is why the safety distance to the side is set very close.

If the rush of visitors to the Rhine Falls is so great that the vehicle can only get through with difficulty or not at all, and thus represents an obstacle for pedestrians, the steward makes use of the head change function at the "Rheinfallbecken" stop.

Aimed findings
Even though the operation at the Rhine Falls per se represents a meaningful mobility offering, it is still an undertaking to gain new insights: How do passengers feel in the steep passages? How does energy consumption change as a result of the more demanding topography? What does the engine temperature curve look like? How does the shuttle progress on its way in the presence the tourists along the Rhine Falls basin? These questions are of interest not only to the operator and the vehicle manufacturer, but also to the Federal Roads Office, which has granted special approval for the operation of the vehicle on this route.

Conclusion
Self-driving vehicles are not yet technically mature. The road to problem-free operation at any time, in any environment and in any situation is still a long one. Nevertheless, pilot tests are not only valuable at the present time, but absolutely necessary, so that industry and society can come to terms with the new possibilities. This is the only way that novel mobility solutions can be created.

"Trapizia" in front of the Rhine Falls: Schlössli Wörth on the right, Schloss Laufen in the background.
Route 12 closes the gap between the city buses in the town centre and the excursion boats in the Rhine Falls basin.
Pedestrians reach the level of the railway station via two lifts and two bridges.
Inspection of "Trapizia" by specialists from the responsible federal offices.
There is not much space at the Rhine Falls basin.