Assessment of the impact of TE33A diesel locomotive wheelsets on the railway track in a straight section of the track

1. Introduction

It is known that the outstanding acceleration is part of the transverse horizontal acceleration of a unit of railway rolling stock acting at the level of the axle box when moving in a circular curve, not compensated by the elevation of the outer rail [1].

Typical design of the upper structure of the track: A structure including a jointless railway track with rails of type R65, reinforced concrete sleepers with a plot from 1,840 to 2,000 pieces per 1 km, crushed stone ballast, or a link railway track with rails of type R65, wooden sleepers with a plot from 1,840 to 2,000 pieces per 1 km, crushed stone ballast [2, 3].

Test (measuring) section of railway track: A section of railway track of limited length intended for conducting complex dynamic (running) and impact tests of rolling stock on the railway track.

The study of dynamic indicators of railway rolling stock is an urgent task for the scientific community. Taking into account the specifics of the railway tracks and the differences in the locomotive fleet, the authors carried out experimental studies using the example of the TE33A diesel locomotive of the Evolution series. The scientific novelty of this study is that for the first time the problems of the impact of the wheel sets of a TE33A series diesel locomotive on a railway track when driving along a straight section of track are considered.

2. Materials and methods

Tests of the locomotive in a straight section were carried out on an odd track of 34 km of the Sorokovaya – Sary-Oba stage. Before the tests, two broken reinforced concrete sleepers were replaced. According to the data of the track measuring car, the condition of the track corresponds to the assessment “good”. The manual measurement data shows that the track width meets the standards [4, 5].

The dynamic performance of the diesel locomotive was measured in the speed range from 60 to 120 km/h. To do this, a diesel locomotive as part of an experimental train consisting of a diesel locomotive and an electric locomotive drove through a section of track equipped with sensors to measure the level of impact on the track at a given speed using the “shuttle” method (Fig. 1 and 2). This study presents the results of experimental investigation of TE33A series diesel locomotive. Fig. 1 and 2 show the results obtained with the help of a mobile vibration measuring complex and with further computer modelling using a personal computer software product of the “Notebook” type. The indicators of frame forces when moving a diesel locomotive on a straight section of track are shown in Table 1.

Fig. 1The coefficient of vertical dynamics of the first suspension stage when moving a TE33A-0023 locomotive on a straight section of track

The values of the coefficients of vertical dynamics of the TE33A pp diesel locomotive of the railway track are shown in Table 2. The data in Fig. 1-2 and Tables 2-3 show that the dynamic performance of a locomotive in a straight section meets the requirements of acceptable standards [6].

Fig. 2The value of the parameters of the vertical dynamics of the TE33A-0023 diesel locomotive

3. Results and discussion

The peculiarity of stress processing in the edges of the sole of the rails is that the data on both rail threads are combined in one row. In this case, the stresses in the outer and inner edges of the sole of the rails are processed separately [7, 8].

The measurement results shown in Fig. 3 and in Table 4 show that the stress level in the edges of the sole of the rail in the straight section under all wheel pairs is almost the same and does not depend on the direction of movement [9]. At the same time, the stress level in the inner edge is slightly higher.

Fig. 3Stresses in the outer edge of the sole of the rail when the TE33A-0023 locomotive is moving along a straight section of track

a) Reverse course

b) Straight course

Fig. 4Half-sum – a) half-difference and b) stresses in the edges of the sole of the rail when moving the TE33A-0023 locomotive along a straight section of track

a)

b)

The maximum probable values of the half-sum are in the range from 70 to 100 MPa. The maximum probable values of the half-difference are significantly lower and range from 20 to 30 MPa [10]. Fig. 4 shows the dependence of the half-sum and half-difference of stresses in the edges of the sole of the rail under the first wheelset of the locomotive [11]. The results of calculations of half-sums and half-differences of stresses in the edges of the sole of the rail in the straight section are shown in Table 5.

Evaluating the obtained stress values in the lower edge of the sole of the rails in the straight section of the track, it can be concluded that the achieved level of 111 MPa values is much less than the maximum permissible value of 240 MPa.

The results of measurements of the lateral forces transmitted from the wheelset guide to the rail are shown in Fig. 5. The level of lateral forces is almost the same for all locomotive wheelsets, does not depend on the speed and direction of movement and the maximum probable value does not exceed 17 kN [12].

Fig. 5Lateral forces from the wheel to the rail when moving the TE33A-0023 diesel locomotive along a straight section of track

a) Reverse course

b) Straight course

The vertical forces from the wheel to the rail increase slightly with increasing speed, and when moving from 60 to 120 km/h, this increase is 18 %. This indicates that in straight sections over the entire range of speeds of the locomotive in the vertical plane, the path has a slight dynamic effect. The level of these forces under all wheel pairs of the locomotive is almost the same [13, 14].

4. Conclusions

As a result of the conducted research, the following conclusions were obtained:

1) The dynamic linear load on the track from the trolley on the straight section of the track and on the switches meets the requirements of the established standards.

2 The stresses on the main site of the roadbed, in the ballast under the sleeper, on the upper bed of wooden sleepers for crumpling under the lining are within acceptable limits.

3) The indicators of the smooth running of the locomotive comply with regulatory requirements when moving at speeds up to structural.

Thus, the compliance of the results of the dynamic study with all regulatory requirements will allow to maintain and further improve the safety indicators in the process of operation of the diesel locomotives under consideration.