Five trains in only four months: Review of the tests conducted on thec-Express in 2023

DB Systemtechnik has completed its tests on the new six-car Desiro HC multiple units from Siemens, which DB Regio Bayern is using to modernise regional transport on the  "Franken-Südthüringen" - Network. Eight of these trains are set to start running from June 2024, primarily on the Nuremberg–Bamberg–Coburg–Erfurt/Sonneberg line, which means they will also travel via the Berlin–Munich high-speed line.

Tests for a top speed of 190 km/h

The trains have to meet special technical requirements to enable them to provide this particular service: they are equipped with the ETCS train protection system, for a start. And with top speeds of up to 190 km/h, they will be among the fastest regional trains in Germany.

This is why the six-car Desiro HC multiple units for the  "Franken-Südthüringen" - Network are going through an approvals process again – unlike the 18 four-car Desiro HC multiple units that DB Regio has also ordered and which will be in service in Franconia and South Thuringia from December 2023 onwards.

Preliminary test on a six-car unit at speeds of 220 km/h

The manufacturer Siemens Mobility handed over the first six-car test train to DB Systemtechnik back in November last year as part of the vehicle authorisation process. By the end of the year, our test experts from Minden and Munich were able to carry out initial tests on a six-car multiple unit, preparing the train for the extensive approval test programme with brake assessments and ramp-up tests at speeds of up to 220 km/h.

Five six-car trains in four months, all simultaneous

The detailed test programme started in February 2023 with five Desiro trains in test operation on the German network simultaneously. Our test teams were able to use these trains to collect all the necessary test results for the subsystems relevant to approval by the end of May, via on-line running tests and bench tests.

Jörg Neugebauer, DB Systemtechnik's project manager for the test campaign, gives a review of the campaign: "Testing from a single source" – this was more than just a slogan when it came to the  "Franken-Südthüringen" - Express. We produced instrumented wheelsets and tested brakes, electromagnetic compatibility, the interaction between the pantograph and overhead line, aerodynamics, acoustics, running equipment and service strength within a very short period of time. We managed to overcome the challenges this posed in terms of planning and resources, working together with our test teams and rail companies to deliver a detailed and efficient four-month programme of test runs.

"Eight" tests on "five" test trains!

The five test trains that Siemens Mobility provided to DB Systemtechnik to carry out the test programme each consisted of two powered end cars and four double-deck trailer coaches. The test teams focused in particular on the braking and running tests, which had to be carried out at high speeds:

• First test train: brake tests up to 200 km/h
• Second test train: tests of service strength (determination of load spectra in the bogie frame)
• Third test train: aerodynamics, acoustics and EMC (rail company services only)
• Fourth test train: running tests up to 220 km/h (vmax + 10%)
• Fifth test train: tests on the interaction of the pantograph and overhead line

For the test runs, "Test train 5" was equipped with four instrumented wheelsets (two powered wheelsets and two carrying wheelsets). The DB Systemtechnik technicians used force measuring sensors to determine the forces that arise between the wheel and the rail of the train. Accelerometers were installed as well.

It was therefore possible to assess the running behaviour, the track stress and the vibration behaviour during running, using the hardware installed on the train and the measured values recorded by it.

Evaluation of the test results with a view to placing the Desiro HC into service

DB Systemtechnik will evaluate all measurements for the Desiro HC, prepare the respective test reports and make them available to Siemens Mobility for vehicle authorisation by June 2023.