Leaving the Applus+ Laboratories quality and safety seal to aid Alstom in Dresden’s tram expansion plan

To accommodate their large number of frequent users, Dresden Transport Services (DVB) set in place a public transport expansion plan. To meet this exciting objective, they've commissioned the design, engineering, and manufacturing of 21 one-way and 9 two-way vehicles to Bombardier Transportation. The Canadian rail manufacturer was acquired by Alstom in 2021. These streetcars will transport thousands of passengers through DVB’s tram lines. Functionality, safety, and quality is indispensable. 

In this instance, our Applus+ Laboratories team had to ensure that Dresden’s new NGT DX DD tram met both EN 12663-1 and VVD 152 standards, structural requirements for railway vehicle bodies. This meant that we had to work closely with both Dresden Transport Services (DVB) and the manufacturer, Alstom.  

The client

Dresden Transport Services (DVB). The backbone of public transport in Dresden. This municipal transportation entity has an extensive 213 kilometres of a rail network, twelve streetcar lines, and 27 city bus lines. Only in 2020, it carried an average of 115.7 million passengers, and this number is only likely to exceed.   

Alstom is a global leader in the transportation sector with extensive expertise in manufacturing vehicles for diverse urban transportation ecosystems, including high-speed trains, metros, and streetcars. Its headquarters are located in France, but they also have a considerable presence in Germany, for example, Bautzen, Saxony, where the NGT DX DD tram vehicles are being manufactured. 

The challenge

Due to the complex vehicle structure and the tight schedule, carrying out the carbody testing for DBV’s latest NGT DX tram presented both technical and organizational challenges. 

The tram has five car body modules: two end modules, short-centre modules with a chassis, and a free-floating sedan module between each of the end carbody modules and the center module. This meant that each distinctive module had to go through a series of static strength tests.

Overall, the testing process implied: 

• The computational design of the carriage bodies   
• Experimental strength testing    
• Measurement runs on the track.  

In this instance, there were two crucial challenges, space capacity for testing and carrying out accurate depictions of the module. The tram vehicle is 43.40 meters long and 2.65 meters wide. The car module is connected with a complex joint system, that had to be successfully reproduced during the testing trials. 

Thankfully, for our Applus+ Laboratories team, every new challenge is a new opportunity to exceed expectations. 

The Solution

Our Applus+ IMA team completed a scope of 53 load cases in under ten days, and Dresden’s new tram vehicle passed the test! The results were positive, and proved that the operational rail vehicles could withstand permanent deformations on the body shell structure and that strains in critical areas of the carbody shell would be able to return to their initial value after removing the load. 

In compliance with both EN 12663-1 and VDV 152, the new tram vehicle withstood:   

• Different loading conditions, including those specified as “extraordinary payload”, with an impact surcharge of 30%.  
• At least 150 kN of traction on the coupling and 200 kN of compression on the connection of impact-absorbing elements.  
• Lifting and derailments, which often accompany the twisting of the carbody structure. The vehicle could withstand 10 mm twists without damage.  

After this last testing phase and two years of development, testing, and certification, the new NGT DX DD tram vehicle for Dresden finally moved on to the dynamic commissioning phase in October 2021, and we can’t wait to see it fully operational this 2023!   

We work arduously to aid manufacturers and suppliers in the railway industry through the validation of their product and prototypes. Forming a part of Dresden’s tram expansion plan by leading its carbody structural test, was a great milestone, but it only became a reality thanks to our full scope of accreditations, cross disciplinary expertise and state-of-the art facilities. 
 

*Special thanks to Thorsten Voigt, Thoralf Grafe and Toni Ehrig, authors of the original article first published in Eisenbahningenieur September 2022 Issue.