The measured values demonstrate that braking distance is also reliably reproducible in the case of emergency braking. The nominal/mean braking distance is set as a design parameter and can be adjusted slightly if necessary.
After the vehicle testing described above had been completed, it was time to begin the homologation process. This involved carrying out a series of test runs in line with the UIC/TSI standards. Once the evidence required by the Polish homologation authority Urząd Transportu Kolejowego (UTK) had been provided, in November 2019 the UTK approved the use of DCC on the NEWAG Impuls 36WEa. The next step will involve a one-year field trial on passenger service.
The lessons learned from the field trial with an Impuls 36WEa multiple unit equipped with active Deceleration Control will also underpin the deployment of DCC in the next generations of Knorr-Bremse braking systems. Deceleration Control and the sensors that it requires will be directly integrated into these new platforms, providing a valuable addition and enhancement to the braking systems’ functionality without the need for additional components or installation work.
The approval of the Impuls 36WEa multiple unit with DCC should be seen as an initial reference project that could potentially enable a far simpler verification procedure for the homologation process. With Deceleration Control, the train’s braking distance variation and adhesion utilization are significantly improved. The amount of work involved in carrying out future test runs should be substantially lower.
At present, the pneumatic brake is solely pressure-controlled and designed for a pre-specified brake pad type. Deceleration Control largely decouples braking distance variation from the tolerances of the braking system and bogie equipment. This means that, in the future, it will be possible to offer optimized friction material configurations, e.g. by finding brake pads that deliver the desired braking behavior while at the same time offering optimal wear behavior with low life cycle costs (LCC), enhanced thermal behavior or optimal noise reduction.
There are also potential value-added application scenarios in everything from Automatic Train Operation (ATO) to fully-fledged driverless systems or routes with platform screen door systems. By reducing braking distance variation, Deceleration Control offers significant benefits in scenarios where vehicles need to brake as precisely and as late as possible.
Authors: Ulf Friesen, Ralf Furtwängler, Norman Kreisel, Jörg Braeseke, Dariusz Ciesielski