RU2487809C2 - Method of track and rolling stock diagnostics - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to flaw inspection and nondestructive checks. Invention consists in using pulses of surface electromagnetic waves radiated forward and/or backward relative to train direction, registering reflection of said pulses from irregularities of the track and defining type of track and/or rolling stock defects from character of said irregularities.

EFFECT: detection of dangerous macroscopic defects at distance exceed stopping distance and registration of derailment.

2 dwg

Description

Technical field

The invention relates to the field of flaw detection and non-destructive testing.

State of the art

The ability to register changes in the state of the rail track during the movement of the train at a considerable distance from the locomotive (within at least one kilometer) is relevant in terms of solving a number of problems of ensuring the safety of transportation:

1. The general tendency to increase the speed of railway transport, the prospective construction of highways, make it important to equip trains with systems that can timely detect the presence of dangerous obstacles or destruction on the route. The fact is that when the speed of the train is ~ 100 km / h, its braking distance during emergency braking is ~ 1 km. Accordingly, the locomotive team, using only visual control of the track, is unable to respond in a timely manner to possible dangerous obstacles, such as landslides, debris, accidentally unhooked wagons of trains ahead of them, destruction of rails by heavy machinery working nearby or crossing the track. Recently, the danger of sabotage destruction has increased. In a sense, high-speed trains move blindly, relying only on indirect data on the degree of route safety.

Such a situation stimulates the study of the possibility of developing a system that can fix the dangerous macroscopic road defects noted above at a distance exceeding the braking distance. A characteristic feature of railways is the presence of curved sections. Therefore, the use of existing methods of terrain control based on radio frequency or laser locations, as well as teleoptic, requiring direct observation of distant objects, in this case seems to be unpromising.

2. The descent of wagons from rails is a serious problem for ensuring the safety of railway traffic. It is also very difficult to register the fact that the car’s wheelsets lose contact with the rails, or that the car has already gone off the rails and rolls on the ties, up to the moment when it rolls over. This is especially true for freight cars that are not equipped with any signaling devices. The length of modern freight trains can be on the order of a kilometer. And it is clear that the driver at such distances is not able to determine by any indirect signs that some car is not traveling on rails.

Attempts have been made to develop methods for detecting the descent of a rolling stock car from rails based on the registration of the accelerations of the non-sprung parts of the rolling stock / 1 / or automatic braking devices of rolling stock when the car is derailed / 2 / . The fact is that the wheels of a car that has gone off the rails, passing on the railroad ties, create mechanical vibrations with the so-called "slew rate", which depends on the speed of the train and the distance between the railroad ties. These vibrations should propagate along the roadway and, through the rails and wheel pairs, should act on the acceleration sensor mounted on the locomotive. However, as shown by experimental work, vibration waves with a sleeper frequency decay very quickly and, in essence, only the carriage adjacent to the locomotive can be reliably detected from the rails. This situation also stimulates the study of the possibilities of developing a system that can fix the descent of cars from rails at a distance corresponding to the length of trains.

The use of microwave technology for the diagnosis of rails in the process of rolling stock is known. B / 3 / microwave radiation is used to detect the displacement of the rail surface, under the influence of vibration and acoustic waves coming out onto the rail surface, by detecting the phase shift of the incident and reflected electromagnetic wave. In this case, a microwave radiation source is installed above the rail surface. The disadvantage of this method is the local nature of its sensitivity.

In addition to the excitation and registration of acoustic waves (vibrational vibrations), eddy currents can be excited on the rail surface (in the skin layer), as well as on the surface of any electrically conductive material. When eddy currents cross a surface defect (crack), the current density changes, which leads to a change in magnetic flux and can be detected. This phenomenon is used in a well-known magnetic (eddy current) flaw detector. This method is the closest in technical essence to the proposed, and therefore selected as a prototype.

The disadvantage of the eddy current flaw detector is that it can detect only those rail track defects that are in the immediate vicinity of the eddy current sensor.

Disclosure of invention

The basis of the invention is the task, by increasing the distance of diagnosing the rail track and rolling stock, expanding the functionality of the method and its scope:

1) detection of dangerous macroscopic defects of the railway at a distance exceeding the stopping distance;

2) registration of the loss of contact of the wheelset of the wagons of the train with the rails.

To achieve the technical task in the method of diagnosing the rail track and rolling stock by exciting alternating electric currents in the surface layer of the rail, registering the electromagnetic field of these currents and analyzing its characteristics, it is new that, to increase the distance of diagnosis, surface electromagnetic pulses are generated in the rail waves propagating in the rail, as in an open waveguide, forward and (or) back along the train, register partial or the total reflections of these pulses from the inhomogeneities of the path (waveguide) and the parameters of the reflected signals determine the presence and nature of the defects of the rail track and (or) rolling stock.

The essence of the invention consists in using the radar principle of searching for targets (defects) and the corresponding time spacing of a relatively powerful electromagnetic pulse emitted into the rail and relatively weak partial reflection pulses from inhomogeneities (defects) of the rail track.

Due to the fact that the methods of remote diagnostics of the rail track and rolling stock based on the use of surface electromagnetic waves are unknown from the prior art, it meets the criterion of "novelty."

Due to the fact that the claimed invention obviously does not follow from analogues and prototype, it meets the criterion of "inventive step".

As will be shown below, the scope of industrial application of the claimed invention can be very broad. Accordingly, the claimed invention meets the criterion of "industrial applicability".

List of drawings

Figure 1 presents the results of calculating the work of a two-element phased emitter on a long line. The directional nature of the radiation is shown.

Figure 2 shows the results of calculating the reflection of an obstacle located on a rail with an effective height of 10 cm.

Information confirming the possibility of carrying out the invention

From an electrotechnical point of view, modern rail tracks are a single-wire transmission line (OLP) of electromagnetic energy, an open waveguide, or a long line. Various types of OLP are known: uncoated wire (Sommerfeld line), wire coated with a dielectric layer (Gubo line), corrugated wire, and others.

Methods for remotely detecting damage in cable lines and power lines are well known. They are based on the excitation in the line of an electromagnetic wave and the analysis of signals reflected from its inhomogeneities.

A distinctive feature of rail tracks is that they have joints. However, rail joints are usually electrically connected using special plates and by soldering, welding or pressing in additional connectors: copper, steel-copper or steel. According to GOST 9.602-89, the increase in resistance of rail threads due to joints should be no more than 20%. The conductive junction, taking into account the requirements of GOST 9.602-89, should have an electrical resistance of not more than the resistance of a whole rail 6 m long - with a length of rail links of 25 m or more. The length of the lash of the jointless (velvet) path can be 550-800 m.

To determine the location of the train on the line, it is divided by joints into isolated sections. Each such section of the track is equipped with a rail chain. The length of the isolated sections varies depending on its required throughput. Accordingly, on the approach to the station and on the station itself, where the speed of movement and the distance between trains are less, the rail chains are shorter than on the stage. Note that, as shown by the experiments, the insulating joints give a strong, but not complete reflection of the probe pulse.

A theoretical study of the problem was carried out by analyzing a system of telegraph equations with parameters corresponding to the railway track.

The main part of the electromagnetic field energy of the surface symmetric E-wave is concentrated in the cylindrical region around the OLP conductor of radius of the order of the wavelength. Thus, the probe pulse should be sensitive not only to objects galvanically connected to the rail, but also to objects electrically isolated from the rail, but located in close proximity to the railway (for example, a car standing on the tracks).

The structure of the surface E-wave has a radial component of the electric field E _r and an insignificant longitudinal component E _z . The magnetic field lines in the form of closed circular lines are perpendicular and symmetrical with respect to the OLP conductor. For OLP, the use of special surface wave excitation devices is necessary. The surface wave excitation device is located in the area of concentration of electromagnetic field energy.

The propagation of the probe pulse (current I and voltage V) along the rail track can be approximately described using telegraph equations:

$$\frac{\partial V}{\partial x}=-L\cdot \frac{\partial I}{\partial t}-R\cdot I\text{(one)}$$

$$\frac{\partial I}{\partial x}=-C\cdot \frac{\partial V}{\partial t}-G\cdot V,\text{(2)}$$

where L, R, C, G are the specific inductance, resistance, capacitance and conductivity characterizing the rail track, respectively.

From (1, 2) we obtain for current:

$$\frac{{\partial }^{2}I}{\partial x^2}=LC\cdot \frac{{\partial }^{2}I}{\partial t^2}+(RC+LG)\cdot \frac{\partial I}{\partial t}+RG\cdot I\text{(3)}$$

We will assume that the parameters L ₀ , R ₀ , C ₀ , G ₀ - characterize a homogeneous path (long line). We introduce the inhomogeneities of the line at the points xc and xr using the delta functions:

$$C={\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="00000040.png"\; state="\{\{state\}\}">C</figure-callout>}}_0+C_{\mathrm{one}}\cdot \delta (x-x_c)\text{(four)}$$

$$R={\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="00000040.png"\; state="\{\{state\}\}">R</figure-callout>}}_0+R_{\mathrm{one}}\cdot \delta (x-x_r)\text{(5)}$$

Imagine the current I in the form:

$$I=I_0+I_{\mathrm{one}c}+I_{\mathrm{one}r},\text{(6)}$$

where I ₀ is the current corresponding to a uniform line, I _1c is the current perturbation caused by capacitive inhomogeneity of the rail track, I _1r is the current perturbation caused by ohmic inhomogeneity of the rail path.

We introduce the parameters of the wave propagation velocity in line v, relaxation time τ, and the inverse decay time of the signal η:

$$\nu =\frac{\mathrm{one}}{\sqrt{L_0{C}_0}}\text{(7)}$$

$$\frac{2}{\tau }=\frac{R_0}{{\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="00000040.png"\; state="\{\{state\}\}">L</figure-callout>}}_0}+\frac{G_0}{C_0}\text{(8)}$$

$$\eta =\sqrt{\frac{R_0{G}_0}{L_0{C}_0}}\text{(9)}$$

We introduce the operator

$$\widehat{L}=\frac{{\partial }^2}{\partial t^2}+\frac{2}{\tau }\cdot \frac{\partial }{\partial t}+{\eta }^2-{\nu }^2\cdot \frac{{\partial }^2}{\partial x^2}\text{(10)}$$

Then the current equation of a homogeneous line will look like:

$$\widehat{L}\cdot I_0(t,x)=0\text{(eleven)}$$

We assume that the current generator is at the origin:

$$I_0(t0)=I_g(t),\text{(12)}$$

where I _g is a given function of time.

Other boundary conditions are the absence of current divergence at infinity.

In the first order of perturbation theory, the equations for currents I _1c and I _1r have the form:

$$\widehat{L}\cdot I_{\mathrm{one}c}=-\frac{C_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="0"\; label="C"\; filenames="00000040.png"\; state="\{\{state\}\}">C</figure-callout>}}_0}\cdot \frac{{\partial }^2{I}_0}{\partial t^2}\cdot \partial (x-x_c)\text{(13)}$$

$$\widehat{L}\cdot I_{\mathrm{one}r}=-\left(\frac{R_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="00000040.png"\; state="\{\{state\}\}">L</figure-callout>}}_0}\cdot \frac{\partial I_0}{\partial t}+\frac{R_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="00000040.png"\; state="\{\{state\}\}">R</figure-callout>}}_0}\cdot {\eta }^2\cdot I_0\right)\cdot \delta (x-x_r)\text{(fourteen)}$$

We make the Fourier transform in current time I ₀ :

$$I_0(t,x)={\displaystyle \underset{-\infty }{\overset{\infty }{\int }}\frac{d\omega }{2\pi }\cdot I_{0\omega }}(x)\cdot \exp (-i\omega t)\text{(fifteen)}$$

$$I_{0\omega }(x)={\displaystyle \underset{-\infty }{\overset{\infty }{\int }}dt\cdot I_0}(t,x)\cdot \exp (i\omega t)\text{(16)}$$

Substituting (15) in (11), we have:

$$\left[-{\omega }^2-\frac{2i\omega }{\tau }+{\eta }^2\right]\cdot I_{0\omega }(x)={\nu }^2\cdot I_{0\omega }^{\text{'}\text{'}\text{'}\text{'}}(x)\text{(17)}$$

Given the boundary condition (12), the solution (17) will have the form:

$$I_{0\varpi }(x)=I_{g\omega }\cdot \exp (i{k}_{\omega }\cdot x),\text{(eighteen)}$$

where I _gω is the Fourier component of the expansion of the generator current function I _g (t).

$$k_{\omega }=\pm \frac{A_{\omega }}{\nu }\cdot \exp \left(i\frac{\delta }{2}\right)\text{(19)}$$

$$A_{\omega }=\sqrt[\mathrm{four}]{{\left({\omega }^2-{\eta }^2\right)}^2+\frac{\mathrm{four}{\omega }^2}{{\tau }^2}}\text{(twenty)}$$

$$tg(\delta )=\frac{2\omega }{\tau \cdot ({\omega }^2-{\eta }^2)}\text{(21)}$$

We study the limit relations. Let ω → 0, then tg (δ) → - 0, therefore δ → π. If ω → ∞, then tg (δ) → +0, therefore δ → 0.

Then finally for a homogeneous line current we can write:

$$I_0(t,x)={\displaystyle \underset{-\infty }{\overset{\infty }{\int }}\frac{d\omega }{2\pi }}\cdot I_{g\omega }\cdot \exp [i(k_{\omega }\cdot x-\omega t)]\text{(22)}$$

Consider an example. Let the generator produce a signal with harmonic ω _g . Let the conditions be satisfied:

$${\omega }_g\tau >>\mathrm{one}\text{(23)}$$

$$\frac{\eta }{{\omega }_g}<<\mathrm{one}\text{(24)}$$

Then we have:

$$I_0(t,x)\approx I_g\cdot \exp \left[i{\omega }_g\left(\frac{x}{\nu }-t\right)\right]\cdot \exp \left(-\frac{x}{\nu \tau }\right)\text{(25)}$$

Solutions of equations (13, 14) can be obtained by the method of Green functions. We define the Green function G (t. X) of the operator L:

$$\widehat{L}\cdot G(t,x)=\delta (t)\delta (x)\text{(26)}$$

Then the solutions of equations (13, 14) will be equal to the convolution of the Green's function with the right-hand sides of the corresponding equations.

We make the Fourier transform of the function G (t, x) in the coordinate:

$$G(t,x)={\displaystyle \underset{-\infty }{\overset{\infty }{\int }}\frac{dk}{2\pi }\cdot G_k(t)\cdot \exp (ikx)}\text{(27)}$$

We have:

$$\frac{{\partial }^2{G}_k(t)}{\partial t^2}+\frac{2}{\tau }\cdot \frac{\partial G_k(t)}{\partial t}+[k^2{\nu }^2+{\eta }^2]\cdot G_k(t)=\delta (t)\text{(28)}$$

Solution (28) has the form:

$$G_k(t)=\frac{\Theta (t)}{{\alpha }_k}\cdot \sin ({\alpha }_{k}t),\text{(29)}$$

where α _k is the solution of the equation:

$${\alpha }_k^2-\frac{2i{\alpha }_k}{\tau }-(k^2{\nu }^2+{\eta }^2)=0\text{(thirty)}$$

Thus, the Green's function of equation (26) can be represented as an integral:

$$G(t,x)=\Theta (t){\displaystyle \underset{-\infty }{\overset{\infty }{\int }}\frac{dk}{2\pi }\cdot \frac{\sin ({\alpha }_{k}t)}{{\alpha }_k}}\cdot \exp (ikx)\text{(31)}$$

It is easy to see that expression (31), convoluted with the right-hand sides of equations (13 and 14), describes the secondary current waves I _1c and I _1r generated by the primary wave I ₀ scattered along the inhomogeneities of the railway track (long line).

This elementary description of the process of translation and scattering of the probe pulse along the line requires substantial refinement. The fact is that the dependence of the ohmic resistance of the line on the frequency can turn out to be very significant. It is known that microwave current does not flow over the entire cross section of a conductor, but only over its surface, in a skin layer of thickness Δ, which depends on the signal frequency. In the SI system, the skin layer thickness is written as follows:

$$\Delta =\sqrt{\frac{2\rho }{\omega \mu {\mu }_0}},\text{(32)}$$

where ρ is the specific electrical resistance of the conductor, µµ ₀ is the relative and absolute magnetic permeabilities of the conductor.

For simplicity, let the conductor have the form of a cylinder of radius r ₀ . Then its specific conductivity R ₀ can be written in the form:

$${\mathrm{<figure-callout\; id="0"\; label="R"\; filenames="00000040.png"\; state="\{\{state\}\}">R</figure-callout>}}_0=\chi \cdot \sqrt{\omega },\text{(33)}$$

Where

$$\chi =\frac{\mathrm{one}}{2\pi \cdot {\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="00000040.png"\; state="\{\{state\}\}">r</figure-callout>}}_0}\cdot \sqrt{\frac{\mu {\mathrm{<figure-callout\; id="0"\; label="\mu "\; filenames="00000040.png"\; state="\{\{state\}\}">\mu </figure-callout>}}_0\rho }{2}}\text{(34)}$$

It is easy to see that in this case, for example, the signal attenuation length vτ, expression (25), will be inversely proportional to the frequency of the electromagnetic pulse:

$$\nu \tau =\frac{2\mathrm{<figure-callout\; id="0"\; label="\nu \; L"\; filenames="00000040.png"\; state="\{\{state\}\}">\nu \; </figure-callout>}{L}_{}{}_0}{\chi \sqrt{\omega }}\text{(35)}$$

Line inhomogeneities lead to partial reflections. In a rail, the speed of propagation of an electromagnetic pulse is close to the speed of light - 300 m / μs. Sensing over a kilometer distance in this case takes time within 10 μs. Taking into account the switching time for the forward and backward locator operation, we will assume that the probe pulse repetition period is 100 μs.

Let the train go at a speed of 120 km / h (approximately 30 m / s). With a probe pulse generation period of 100 μs, there is the possibility of repeated repetition of “experiments” to study the state of the railway track, both “forward” and “backward”. So, in 1 second the number of experiments N = 10000 will be carried out. Statistical processing can allow, using mathematical methods of signal processing, to suppress noise and isolate the signal from the defect. It is known, for example, that when conducting N experiments, the measurement errors of the quantities decrease inversely with the square root of N.

An analysis of the nature of the reflection of a signal in rails from defects of a track of various types shows that with a continuous destruction of the rail track, the reflection coefficient K = 1 for all pulse harmonics. If there is a local attached capacitance on the line, which physically may correspond, for example, to a car standing on the track, the reflection coefficient contains two terms proportional to the frequency in the first and second degree. Estimates show that it is possible to register metal objects located at a shallow depth below the surface of the roadbed.

Thus, the analysis of the amplitude-frequency characteristics of the reflected signal can allow us to draw conclusions about the nature of the rail track defect.

Technically, the generation of the probe pulse and registration of the reflected pulse can be provided by both induction and capacitive devices.

The simulation results show that it is possible to form directional radiation (back and forth) with the help of several simple radiators powered with a phase shift (phased array antenna).

Consider the formation of a directed pulse in rails. Let us have the simplest phased emitter, consisting of two elements. The first emitter is located at the origin and forms a wave φ _{1 of} unit amplitude and frequency ω in the line described by expression (36).

$${\varphi }_{\mathrm{one}}(t,x)=\Theta (x)\cdot \sin \left[\omega \cdot \left(t-\frac{x}{\nu }\right)\right]+\Theta (-x)\cdot \sin \left[\omega \cdot \left(t+\frac{x}{\nu }\right)\right],\text{(36)}$$

where v is the wave propagation velocity in the line.

The second radiator is located at a point with the coordinate a = λ / 4, where λ is the wavelength, and forms a wave φ ₂ with a phase delay relative to wave φ ₁ by a / v.

$${\phi }_2(t,x)=\Theta (x-a)\cdot \sin \left[\omega \cdot \left(t-\frac{x}{\nu }+\frac{a}{\nu }-\frac{a}{\nu }\right)\right]+\Theta (a-x)\cdot \sin \left[\omega \cdot \left(t+\frac{x}{\nu }-\frac{2a}{\nu }\right)\right]\text{(37)}$$

Due to the linearity of the wave equations, waves φ ₁ and φ _{2 are} added. The total wave φ = φ ₁ + φ ₂ will have the form:

$$\phi (t,x)=\Theta (x-a)\cdot 2\sin \left[\omega \cdot \left(t-\frac{x}{\nu }\right)\right]-\Theta (x)\cdot \Theta (a-x)\cdot 2\sin (kx)\cdot \cos (\omega t)\text{(38)}$$

where k = 2π / λ.

Thus, in this case, a standing wave is formed between the emitters. Forward, behind the emitters, a wave of doubled amplitude propagates. Back behind the emitters, the waves cancel each other out.

In general, studies have shown that the entire locator device can be made compact enough to have low power consumption (~ 1 W) and can be installed on any rail vehicle.

The structural composition of the electromagnetic sounding system

The system should consist of two radar channels (one for each rail), an accurate positioning device (Glonass or GPS), a memory block with a picture of a “defect-free path” (for example, reflections from insulating joints and arrows) and normal reflections from the wheelsets of train cars , as well as a computer that provides real-time comparison of radar pictures of the defect-free path and normal reflections from the wheelsets of train cars with the currently controlled one;

The radar should consist of a specially shaped adjustable electric pulse generator; a switch providing alternate transmission of a pulse to each transceiver antenna; synchronizer, providing the opening of the input of the amplifier of the receiver for a certain time interval corresponding to the time of arrival of the reflected signal.

The memory unit must provide the introduction and storage of parameters of the reflected pulses corresponding to the normal state of the track and the normal state of the cars.

The power supply must ensure the operation of the System from standard on-board power supplies.

The on-board computer of the System, based on appropriate software and taking into account data on a faultless path, should ensure the processing of the received information with the issuance of an opinion on the degree of safety of the route and on the condition of train cars.

Additional features

The so-called magnetoelastic effect or Villari effect is known, which consists in the fact that under the action of mechanical stresses the magnetic properties of bodies change (see, e.g., / 4 /), in particular, the magnetic permeability of ferromagnetic steels, including rail.

The depth of the skin layer, in which an electromagnetic pulse propagates along the surface of a ferromagnetic conductor (rail), depends on magnetic permeability. And the specific electrical resistance of the line (rail track) depends on the depth of the skin layer. Line inhomogeneities lead to partial reflections. Sounding over a kilometer distance in this case (taking into account the propagation velocity of the electromagnetic pulse ~ 300 m / μs) takes time within 10 μs. Taking into account the switching time for the forward and backward locator operation, we will assume that the probe pulse repetition period is 100 μs. The wagon wheel has a diameter of 1 meter and, accordingly, a circumference of approximately 3 m.

Let the train go at a speed of 120 km / h (approximately 30 m / s). Then, if there is a defect on the wheel (for example, a flat or slider), then with a period of 0.1 second, it will hit the rail, generating excess deformation waves and changing the reflection pattern. At a probe pulse generation frequency of 100 μs, this picture should be well recorded and, for example, for 100 s the “experiment to detect a defective wheel” will be repeated 1000 times. This can allow, using mathematical methods of signal processing, to suppress noise and isolate the signal from the defect.

Thus, there is a theoretical possibility of remote monitoring of some rolling stock defects.

If it becomes possible to determine with sufficient accuracy the coordinates of the wheelsets of the cars, and, accordingly, the cars themselves, it will be possible to determine the degree of stretching / compression of the couplers of the cars. This information can be used to select the optimal operating mode of the locomotive power plant.

A rail locator can be an independent source of information about the breakage or undocking of one or a group of cars from the rest of the train.

Finally, despite the increased number of insulating joints on access roads, the rail locator can serve to prevent collisions between maneuvering locomotives

Information sources

1. Merkulov V.I .; Misevich V.N .; Slavinsky Z.M .; Troshkina E.I .; Sharadze O.Kh. RF patent №2137633 from 08.09.1998.

2. Smirnov V.V .; Merkulov V.I .; Misevich V.N .; Slavinsky Z.M .; Sharadze O.Kh .; Kulemin V.N .; Yerilin E.S .; Spiridonov E.S. RF patent №2137632 from 09/08/1998.

3. Kudinov D.S., Shaidurov G.Ya. Method for non-destructive testing of railway rails in the process of rolling stock movement and device for its implementation. RF patent No. 2380259 dated November 17, 2008.

4. E.S. Gorkunov, S.Yu. Mitropolskaya, A.L. Osintseva, D.I. Vichujanin. “The study of deformation and stress assessment in materials with a hardened surface layer by magnetic methods” Physical mesomechanics. 12 2 (2009) 95-104.

Claims (1)

A method for diagnosing a rail track and rolling stock by exciting alternating electric currents in a surface layer of a rail, detecting the electromagnetic field of these currents and analyzing its characteristics, characterized in that for increasing the distance of diagnosis, pulses of surface electromagnetic waves propagating in the rail are generated in the rail, as in the open waveguide, in the directions “forward” and (or) “backward” along the train, register partial or total reflections of these pulses from the inhomogeneities of the path (waveguide) and the parameters of the reflected signals determine the presence and nature of the defects of the rail track and (or) rolling stock.

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