The results of the coupling and driving trials with the tested prototypes are very different. One thing the couplings of all manufacturers have in common is that deficiencies and weaknesses were identified over the course of the tests, and repairs were required on all coupling designs. It was only possible to generate a comprehensive data base for all the prototypes included in the test by extending the test, as explained in the introduction, and with the repairs carried out by the manufacturers. The following examines the three DAC designs individually and lists the results in summary form for each design.
Scharfenberg design from manufacturer Voith
The driving trials ran overall without any noticeable problems. All infrastructures could be negotiated without restrictions. The coupling procedures with the first version of the Voith DAC failed in numerous cases. The electrical coupling procedures were also assessed as “not successful” in many cases (e.g. 24 of 72 trials at 6 km/h not successful). The contacts often externally showed clear wear marks after just a few trials which was determined as the cause for the negative assessment. In detail, it proved to be only a few contacts which had failed permanently. Voith has developed and made available a version 1.2 on which the coupling head has been adapted. During the coupling trials with this second version of the DAC design, the coupling procedures were successful at lower and medium speeds. The carriages only recoiled with not coupling procedure during coupling trials at 12 km/h. The problems with the contacts in the electrical coupling remained unchanged with version 1.2 of the prototypes.
Latch-type design from the manufacturer Dellner
The first generation of the Dellner latch-type design did not meet the requirements for mechanical strength, meaning that Dellner had to pronounce restrictions in relation to the coupling impacts. Specifically, coupling impacts at speeds higher than 10km/h were not permitted. However, the mechanical and pneumatic connections during the coupling procedures tested 100% successfully allowing for the restrictions. The second generation of the coupling included a mechanical upgrade of the DAC and the implementation of a stabilisation joint to improve the resistance to derailing.
The electrical coupling procedures were assessed as “not successful” in many cases (e.g. 27 of 27 trials at 2 km/h not successful). Also, the contacts often externally showed clear wear marks and the moving contact side jammed after just a few trials. In many cases, as is the case of the Voith coupling results, the failure of individual contacts was the cause for the negative result of the assessment. However, in at least one case, both E-couplings failed completely.
The driving trials with the generation 1 prototypes ran overall without any noticeable problems. All infrastructures could be negotiated without restrictions.
Schwab design from the manufacturer Wabtec
The Schwab prototype also required a second version in order to produce results which were suitable for assessment. With the DAC prototypes tested, the mechanical connection during the coupling procedures tested 100% successfully. The pneumatic coupling did not work in some cases (e.g. 12 of 104 trials at 2 km/h not successful). It was in part possible to couple Zags and Hbbins carriages in the 100 metre bend depending on the load of the Hbbins. It was not possible to couple Zags and Hbbins carriages in the 75 metre bend.
Constructional weaknesses on the moving parts of the electrical contact coupling arose during the tests. As a result, during most of the trials, the reports state that the electrical connection was not successfully closed (e.g. 48 of 104 trials at 2 km/h not successful).
Selected follow-up tests were carried our with the retrofitted E-couplings. In the process, it was only possible to reassess a limited speed range. In these follow-up tests, the measures taken were successful. There were not noticeable significant wear marks in the case of the E-contacts.
The driving trials were mechanically and electrically 100% successful. However, problems with the pneumatic connection were identified (pneumatically coupled in 30 of 142 trials not successful). In this case, there were no short-term air losses.
Over the course of the trials, the required force in order to separate two decoupled carriages proved to be greater and greater. This behaviour was eradicated towards the end of phase I by Wabtec by directing the coupling heads sideways in advance using an adapter on the coupling rod. As a result, the decoupling force seemed to have returned to within an acceptable scope. It was only possible to test this to a limited extent within the remaining time.