“Yes, it is more expensive: the daily cost of spraying poison on the tracks is 2,000 francs. With the hot water-steam system, the daily costs rise to around 6,000 francs,” explains Patrik Bösch (39), Director of Railway Services at Rigi Bahnen AG.
Instead of just using the controversial herbicide glyphosate, Rigi Bahnen now uses hot water and steam to drive weeds off the rails. Unwanted plants should be removed for safety reasons, because vegetation closes the gaps in the ballast bed, making the rail system a solid mass, air (rainwater does not discharge), temperature effects (freezing of compact mass lifts the load) pallet bed, no vegetation, frost can spread into the gaps) and traffic loads can cause deformation of the pallet body.
Why do railroads pay more?
With the hot water-steam process, the process costs about three times more than poison. Why does Rigi Bahnen pay so much more? “We want to be part of the solution. Instead of just injecting poison, we’re trying to help develop something more sustainable,” says Bösch.
“Of course you could say it’s nonsense – but it’s important to us as a company,” he agreed. Even as a private person, he wants to leave his two sons a natural environment where they can “enjoy”.
alternative to poison
The former structural painter and bricklayer is responsible for 16 kilometers of rack railway line, bridges, walls and weeds, as well as desired planting at Rigi Bahnen. So far, glyphosate has been sprayed outside of groundwater protection zones in the spring and autumn. The so-called total herbicide will kill any non-genetically modified plant such that it survives application. As a result, glyphosate destroys biodiversity.
Today, Rigi Bahnen uses the hot water-steam process once a year. They report their experience to the manufacturer Müller Gleisbau AG from Frauenfeld TG, thereby helping to improve the process. “We hope it will be suitable for all railways and be cheaper as a bulk product,” explains Bösch. During the tests, he saw how well the method worked and the weeds disappeared.
This is how the procedure works
A sweep is used to destroy weeds. Among other things, the tank is loaded onto the furnaces and nozzles and then pushed up by the traction vehicle. The steam mixture is heated to 130 degrees and sprayed onto the plants in the runway area by means of a nozzle.
Black rubber flaps are used on the rails to prevent the water from cooling. Water vapor escapes from the bottom. The heat from the steam triggers a protein shock in the plant that destroys the cell wall. As a result, the plant can no longer absorb water and dries up.
First, Rigi Bahnen tested the process with a handheld device. “But it was very time consuming,” says Bösch. Müller Gleisbau AG then made them a custom-made product that fits in a boxcar or low loader. “We have modified the system so that it can be used practically for the rail network,” explains Werner Messmer (61), Managing Director of Grün & Forst at Müller Gleisbau AG and also responsible for the cooperation with Müller Technology.
Waste of energy against poison?
Both Messmer and Bösch are aware that the hot water-steam process consumes a lot of energy. In particular, they want to improve the heating of hot water with fuel oil. One of his ideas is: “We’re trying to use used cooking oil and biodiesel instead of heating oil,” explains Messmer.
They’ve already implemented another idea: they use warm water instead of cold water, which means less energy is used to heat it. For example, while on the Appenzell Railways, they used hot wastewater from the production of Appenzeller breweries.
“Continuing to improve the system requires brain power,” Bösch says with a laugh. Thanks to the pioneering railways, the system continues to evolve in this way. “The hot water steam system can be used across the entire railway network in Switzerland,” says Messmer. And then there would be no longer any need for poisons that mingled with the soil and groundwater.