# Theory and Practice of Determining the Dynamic Performance of Traction Rolling Stock
## 8 Conclusions  
The performed studies allow us to draw the following main conclusions:  
* Experimentally obtained values of the vertical dynamics coefficients of the first and second stages of the spring suspension of the tested diesel locomotive CKD6E-2108 did not exceed the permissible limits, and the maximum values for the vertical dynamics coefficients were 0.11 for the first stage and 0.25 for the second stage. In this case, it should be noted that the obtained limit value of 0.25 of the vertical dynamics coefficient of the second stage was recorded when moving at a speed of 90 km/h, which is 12.5% higher than the designated speed [18];
* The experimentally obtained maximum value of the ratio of frame forces to the static load from the wheelset on the rails was 0.08;
* The obtained minimum value of the stability factor against derailment of the wheel on the straight section of the track was much higher than the standard value;
* Thus, the speed of movement along straight sections was in accordance with the norms for permissible movement speeds according to the assessment of dynamic indicators, which may be limited by the declared designated speed of the type of rolling stock under study [20]:
* Experimentally obtained dynamic performance of the investigated diesel locomotive CKD6E-2108 (the ratio of frame forces relative to the static load from the wheelset on the rails, the coefficients of vertical dynamics of the first and second stages of suspension and the stability factor against derailment of the wheel from the rail were registered on the track section in a curve with a radius of 400 m) meet current requirements;
* The design scheme and the equation of vertical oscillations were developed.  
Using the MathCAD application system:
* An analysis was carried out according to the schedules of movements of the bogies and the body of the locomotive when moving along irregularities of different lengths at different speeds;
* With an increase in speed from 40 km/h to 120 km/h, the amplitude of the bogie oscillation changed (increases), which had a negative effect on the dynamics of the locomotive. On short bumps with the highest speed, the dynamics of the locomotive worsened [3];
* With a long roughness of the track, the amplitude of oscillations was significantly reduced and the smoothness of the movement of the locomotive increased, which did not affect the dynamics of the locomotive.
* Further studies of the dynamic and operational characteristics of the studied diesel locomotive CKDoe can be supplemented as information related to the operation, repair and maintenance of the studied brand of diesel locomotive when it becomes available.  
Conceptualization, J.M.; methodology, J.M. and A.Z.; software, A.Z.; validation, A.Z. and J.M.; formal analysis, A.Z. and J.M.; investigation, A.Z. and J.M.; resources, S.Y. and S.I.; data curation, S.Y. and S.I.; writing--original draft preparation, A.Z.; writing--review and editing, A.Z. and J.M.; visualization, J.M.; supervision, J.M. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Academy of Logistics and Transport.  
This study did not require ethical approval.  
Not applicable.  
All data products generated in this study (velocity models, the performed studies) are available from the authors upon request.  
This work received financial support from the Academy of Logistics and Transport and was performed at the Institute of Transport Engineering, which is gratefully acknowledged by the authors.  
Conflicts of Interest: The authors confirm that they have no conflict of interest with respect to the work described in this manuscript.