Railway track with the increased resistance to thermal expansion of rails

Abstract

The invention relates to a railway track with straight sections (1), transition curves sections (2) and arc-shaped sections (3) comprising a ballast layer on which railway sleepers are laid out on which the rails are mounted wherein radially milled rails are placed on straight sections (1), movable railway sleepers and vertically on one side milled rails are placed on the transition curves sections (2) and on the arc-shaped sections (3).

Description

[0001] Railway track with the increased resistance to thermal expansion of rails

[0002] The object of the invention is a railway track with increased resistance to distortion (buckling) associated with thermal expansion of rails, especially for use in the jointless joining of railway rails.

[0003] In geometric systems of railway track, described in patent documentation GB565873 as well as in normative publications as for example PN-EN 13803 for the current state of the art in relation to the railway track axis (Fig. 1) straight sections 1, transition curves 2 and arc-shaped sections 3 can be distinguished. Known solutions that counteract the distortion of railway tracks due to thermal expansion of the rails involve the use of the rail expansion joints on straight sections of the tracks, particularly the oblique joints, as described, for example in patent documentation RU2090685. Fig. 1 shows a top view of the railway track axis on straight sections 1, transition curves 2 and arc- shaped sections 3.

[0004] Previous solutions presenting railway tracks have a common feature being a low resistance to thermal expansion of rails and excessive mass and high manufacturing costs, and moreover they do not allow for the manufacturing of jointless joining of tracks with radii lower than 300 m. This problem is significant enough that there are known cases of rail buckling threatening the safety of railway track users. This phenomenon is known as a „rail stressing” and manifests itself as a sudden change in the geometry of the railway track due to the release of thermal stresses (longitudinal forces) in the rails. Under the influence of temperature differences, the railway rail can undergo buckling thus preventing safe exploitation of railway tracks.

[0005] This technical problem is solved by the present invention by providing an improved and defect- free railway track with increased resistance to the thermal expansion of rails compared to previously known solutions.

[0006] The aim of the invention is to deliver an improved railway track with increased resistance to the thermal expansion of rails that will eliminate inconveniences associated with the thermal expansion of rails leading to their buckling (rail stressing); high costliness in the production of rails; inconveniences related to excessive mass of the rails and will enable manufacturing of the track with a smaller radii of the horizontal arc.

[0007] The object of the invention is a railway track with straight sections, transition curves sections and arc-shaped sections comprising a ballast layer on which railway sleepers are laid out, on which the rails are mounted characterized in that radially milled rails are placed on straight sections, movable sleepers [pl. podklady wahliwe] and vertically on one side milled rails are placed on the transition curves sections and on the arc-shaped sections.

[0008] Preferably, radially milled rails constitute radially vertically on both sides milled rails or radially horizontally on both sides milled rails.

[0009] The essence of the invention is to present a solution which increases resistance of railway track, in particular jointless one, to the phenomenon of rail buckling (rail stressing) by:

[0010] - the use of rails with increased resistance to thermal buckling on straight sections of the track (vertically on both sides milled rail, horizontally milled rail);

[0011] - the use of vertically on one side milled rails on the track curvature sections ;

[0012] - the use of movable railway sleepers on the track curvature sections enabling the compensation of thermal stresses in rails. These stresses occurring in the longitudinal direction of the track axis, are transformed via movable railway sleepers into rail displacements in the transverse direction to the track axis, as shown in Fig. 2.

[0013] The advantage of the invention compared to the state of the art is that it provides increased resistance of the railway track to the thermal expansion of rails, decreases the expenditures of the rail production, decreases the expenditures to the track construction due to the use of the lighter rails, decreases the expenditures to the track construction due to the less frequent use of expansion joints as well as enable the manufacturing of the jointless track of radius smaller than 300 m.

[0014] Examples of embodiments according to the invention are shown in the drawing, in which Fig. 2 shows a top view of the railway track axis, Fig. 3 shows in a perspective view a movable railway sleeper, Fig. 4 shows a rail with radial cutouts in a general view and in cross-sections, Fig. 5 shows a rail with radial cutouts on one side in a general view and in cross-sections, Fig. 6 shows cross-sections of the rail in the area of radial vertical cutouts, Fig. 7 shows a rail with radial horizontal cutouts in a general view and in cross-sections, and Fig. 8 shows cross-sections of the rail in the area of radial horizontal cutouts.

[0015] A railway track is an infrastructure intended for the movement of rail vehicles, such as trains. It consists of two parallel rails placed at a fixed distance from each other, on which the wheels of the rail vehicles move. The railway track is a fundamental element of the railway system, enabling the movement of vehicles on specified routes.

[0016] The axis of the railway track with increased resistance to thermal expansion of the rails is shown on straight sections 1, transition curves 2 and arc-shaped sections in the middle position 3, as well as at the minimum thermal expansion in position 3a and at the maximum thermal expansion in position 3b.

[0017] The example of the embodiment illustrated in Fig. 2 shows a railway track having increased resistance to distortions associated with thermal expansion of the rails. The increased resistance of the railway track to distortions associated with thermal expansion of the rails results from the use, on the straight sections of the track marked as 1 in Fig. 2, of the radially vertically on both sides milled rails or, in an alternative example of the embodiment, of the radially horizontally milled rails.

[0018] The railway track having applied movable sleepers and vertically on one side milled rails on the track curvature sections, i.e., arcs marked as 3 in Fig. 2 and transition curves marked as 2 in Fig. 2, enables the change of the geometry of the above mentioned curvatures. On the track curvature sections, its construction allows the railway rails to displace in the transverse direction 4 in Fig. 2 to the track axis on the curvature sections, i.e., on the arc-shaped section 3 and transition curves 2. The extreme positions of the track axis caused by the phenomenon of the thermal expansion of the rails are marked in Fig. 2 as 3a and 3b. In a preferable variant of the railway track embodiment, it is possible to use movable sleepers on the track curvature sections, i.e., on the arc-shaped section 3 and transition curves 2 shown in Fig. 2. It is also preferable to use radially vertically on one side milled rails on the track curvature sections, i.e., on the arcshaped sections 3 and transition curves 2 shown in Fig. 2. It is also preferable to use radially horizontally milled rails on the straight sections of the track as shown in Fig. 2.

[0019] Movable railway sleeper

[0020] The movable railway sleeper (Fig. 3) used in the invention has a construction that allows the displacement of both installed on it railway rails TS in the transverse direction KP to the track direction KT, without changing of the rail gauge W in the railway rails TS. Movable railway sleeper comprises a base 5, fixed in place in relation to the subgrade 6, a movable part 7, slidingly movable on sliding surfaces 8 and 9 in the longitudinal direction KP relative to the base 5 and thus transverse relatively to the track direction KT.

[0021] The base 5 is an appropriately profiled beam with proper stiffness made of, for example prestressed concrete, other composite materials, metal or wood.

[0022] Subgrade 6 is an earth structure that transfers loads from the rolling stock on the track to the native soil or embankment fill. In a specific cases the base 5 may be fixed in place in relation to the subgrade 6 by the use of the railway ballast. The movable part 7 is an appropriately profiled beam with proper stiffness made of for example prestressed concrete, other composite materials, metal or wood. It is preferable to manufacture the movable part 7 and the base 5 from the prestressed concrete with embedded therein steel shapes forming sliding surfaces 8 on the base 5 and the counterparts 9 of those sliding parts on the movable part 7. Then, for lubrication of the adjacent sliding surfaces at the junction of the base 5 and the movable part 7 can be used for example a lubricating agent approved by PKP PKL S.A. for lubrication of the friction parts in railway turnouts.

[0023] The sliding surfaces 8 and 9 are planes made of a material appropriately resistant to abrasion (for example metal) at the base 5 and in the movable part 7. The use of lubricant that reduces friction between the sliding surfaces 8 and 9 in a preferred manner influence the system performance. A shape (or rather a relative position) of the sliding surfaces as shown in Fig. 3 prevents the movement of the movable part 7 in relation to the base 5 in the direction KT, longitudinal to the track axis.

[0024] Radially vertically milled rail

[0025] A radially vertically milled rail 11 is shown in Fig. 4, 5 and 6, its cross-section is variable in its length in a manner resulting from realisation of the radial cutouts with the radii RQ as show in in Fig.4 by milling on the rail in regular intervals of S5.

[0026] Simplified cross-section, marked as 15 in Fig. 4, of the rail with the radial cutouts, made in the axis of symmetry of the railway sleeper, marked as 2 in Fig. 4, is close to the cross-section of the rail described in PN-EN 13674-1 standards. Similarly as in the solutions known from the art, it is possible to distinguish here a foot 65, a neck 55 and a head 45 of the rail 11. Simplified cross-sections C4-C4, D4-D4 from Fig. 4 and E5-E5 from Fig. 5, made in the area of the radial vertical cutouts are shown in Fig. 6.

[0027] Fig. 4 shows the normalized rail (11) in the cross-section view. The rail (11) has dimensions typical for standard railway rail (comply with PN-EN 13674-1 standard requirements), that is total height is 149 mm (for 49E1 rail), 172 mm (for 60E1 rail), width of the foot (65) is 125 mm (for 49E1 rail), 150 mm (for 60E1 rail). The rail is manufactured from i.e. carbonmanganese steel R260 or R350 HT.

[0028] Along the entire length of the rail (11), on both sides of the foot (65), the radial cutouts with the radius RQ were made by milling in regular intervals of S5. The radius (RQ) of the cutout is 610 mm (in the case of the sleeper gauge of 0.6 m) or 1400 mm (in case of the sleeper gauge of 0.8 m). Minimum value of the one sided excess (K5) of the foot (65) of the rail (11) in the area of cutouts is 0.1 of the railway sleeper width (P5), that has a width equal to 160 mm at the point of the rail support. A minimum width (G) of the neck (55) of the rail (11) is not smaller than the value according to PN EN 13674-1.

[0029] Fig. 5 shows the rail (11) along the entire length of which, of inner side of the foot (65) relative to the direction of the track arc radius (RT) the radial cutouts were made by milling in regular intervals of S5. The radius (RJ) of the cutout is 610 mm (in the case of the gauge S5 of the sleeper of 0.6 m) or 1400 mm (in the case of the gauge S5 of the sleeper 0.8 m). Minimum value of the one sided excess (K5) of the foot (65) of the rail (11) is 0.1 of the width (P5) of the railway sleeper (that is min K5 = 0.1XP5), that has the width P5 of 160 mm at the point of the rail support. Minimum width (G) of the neck (55) of the rail (11) is not smaller than the value according to PN-EN 13674-1. The rail with radial cutouts is intended for the use in the sleepery railway tracks with regular gauge of sleepers, marked as S5 in the axis of symmetry of the sleepers in Fig. 4 and Fig. 5.

[0030] It is preferable to use the radial cutouts because this shape of the cutout minimalize probability of the occurrence of the notch phenomenon. It is preferable to use the rail with the radial vertical cutouts made on both sides of the foot of the rail as shown on Fig. 4.

[0031] On the curvature, arches and transition curves sections of the railway track, it is preferable to use the rail with radial vertical cutouts made on one side of the foot of the rail, on the inner side of the foot of the rail in respect to the direction of track arc radius RT, according to Fig. 5.

[0032] The rail 11 with a radial cutouts is manufactured by radial milling made on an existing finished product, for example on the one described in the PN-EN 13674-1 standards with maintaining the dependence shown in Fig. 4 and Fig. 5, and relating to the minimum amount of the one sided excess (overhang) K5 of the foot 65 of the rail 11 from the railway sleeper 25 (i.e. min K5 = 0.1XP5). The value of the cutout radius RQ results from the abovementioned dependency as well as the circumstances as presented in Fig. 4. The value of the cutout radius RJ results from the abovementioned dependency as well as the circumstances as presented in Fig. 5. It is also important that the minimum width (G) of the neck (55) of the rail (11) that was achieved as a result of a radial cutout as in Fig. 4 and in Fig. 5 was not smaller from the primary value according to PN-EN 13674-1. The process of the manufacturing of railway rails will not be changed but only an additional machine processing of the final product will be done by the radial cutout.

[0033] It is possible to manufacture the rail with radial vertical cutouts as a separate final product. Radially horizontally milled rail

[0034] Drawings of a radially horizontally milled rail 17 is shown in Fig. 7 and 8, the cross section of which is variable along its length due to the realisation of the radial horizontal cutouts as shown in Fig. 7 that were made by milling with radii RP in regular intervals equal to S7.

[0035] Simplified cross-section marked as 18 in Fig. 7, of the rail with the radial horizontal cutouts, made in the axis of symmetry of the railway sleeper marked as 27 in Fig.7 is close to the crosssection of the rail described in the widely available PN-EN 13674-1 standards. Similarly as in the solutions known from the art, here it is possible to distinguish a foot 67, a neck 57 and a head 47 of the rail.

[0036] Simplified cross-sections C7-C7, D7-D7 and E7-E7 from Fig. 7 made in the area of the radial horizontal cutouts are shown in Fig. 8. The rail with radial horizontal cutouts realised by for example milling or embossing is intended for the use in the sleepery railway tracks with regular gauge of sleepers, marked as S7 in the axis of symmetry of the sleepers in Fig. 7. It is preferable to use the radial horizontal cutouts because this shape of the cutout minimalize probability of the occurrence of the notch phenomenon. The rail with a radial horizontal cutouts can be manufactured by radial cutting made on an existing finished product, for example on the one described in the PN-EN 13674-1 standard while maintaining the dependence shown in Fig. 7, that relates to the minimum value of the length H of the neck (i.e. min H = h*4 / 5) as well as the minimal value of the one sided excess (overhang) of the foot 67 of the rail 17 from the railway sleeper 27 (i.e. min K7 = 0.1 *P7). The value of the radius RP of the cutout results from the abovementioned dependency and the circumstances as presented in Fig. 7.

[0037] Fig. 7 shows the normalized rail 17 in a transversal cross-section. The rail 17 has dimensions typical for standard railway rails (comply with PN-EN 13674-1 standard requirement), that is total height of the rail is 149 mm (for 49E1 rail), 172 mm (for 60E1 rail), the foot (67) width is 125 mm (for 49E1 rail), 150 mm (for 60E1 rail). The rail is manufactured from i.e. carbonmanganese steel R260 or R350 HT. Length of the rail neck 57 for 60E1 rail is h = 89.5 mm and for 49E1 rail is h =70 mm. Width P7 of the sleeper 27 is 160 mm at the point of the rail support.

[0038] Along the entire length of the rail 17 radial cutouts with the radii RP were made by milling in a regular intervals of S7, passing through the rail foot 67 and partially through the rail neck 57. The radious (RP) of the cutout is 288 mm (in the case of gauge S7 of the sleepers 27 is S7 = 0.6 m) or 623 mm (in case of gauge S7 of the sleepers 27 is S7 = 0.8 m) - rail 60E1. For rail 49E1 the radious (RP) of the cutout is 350 mm (for S7 = 0.6 m) or 779 mm (for S7 = 0.8 m). The rail with the radially horizontally cutouts can be made as a separate finished product maintaining the dependency as shown above in Fig. 7.

[0039] Present invention may be applied in the railway industry, particularly in the construction of railway tracks of rails

[0040] List of reference marks

[0041] 1 - straight section of the railway track

[0042] 2 - transition curve of the railway track

[0043] 3 - arc-shaped section of the railway track

[0044] 3a - position of the axis of the track symmetry in the state of maximum thermal rail shrinkage

[0045] 3b - position of the axis of the track symmetry in the state of maximum thermal rail elongation

[0046] 4 - direction of thermal displacement of railway rails, transverse to the track direction

[0047] 5 - base of the sleeper

[0048] 6 - subgrade

[0049] TS - railway rail

[0050] 7 - movable part of the sleeper

[0051] 8 - sliding surfaces in the base of the sleeper

[0052] 9 - sliding surfaces in the movable part of the sleeper

[0053] KP - direction of the movement of the movable part of the sleeper on the base of the sleeper

[0054] KT - direction of trains movement identical to the track direction, transvers to the direction KP

[0055] W - fixed rail gauge in the railway rail

[0056] 11 - radially vertically milled railway rail

[0057] 15 - simplified cross-section of the radially vertically milled railway rail made outside of the milling area, i.e., in the axis of symmetry of the railway sleeper 25

[0058] 25 - railway sleeper for rail 11,

[0059] F5 - axis of symmetry of the railway sleeper 25 S5 - gauge of railway sleepers 25 in the axes of symmetry F5 for the radially vertically milled rail

[0060] 34 - arc-shaped surface formed as a result of a radial cutting with the radius RQ

[0061] 35 - arc-shaped surface formed as a result of a radial cutting with the radius RJ

[0062] 45 - head of a radially vertically milled rail

[0063] 55 - neck of a radially vertically milled rail

[0064] 65 - foot of a radially vertically milled rail

[0065] C4 - C4 characteristic cross-section of a radially vertically milled rail

[0066] D4 - D4 characteristic cross-section of a radially vertically milled rail

[0067] E5 - ES characteristic cross-section of a radially vertically milled rail

[0068] G - minimum width of the neck of a radially vertically milled rail

[0069] K5 - amount of one sided excess (overhang) of the rail foot from the railway sleeper

[0070] P5 - width of the railway sleeper for the radially vertically milled rail

[0071] RQ - radii of cutouts resulting from radial vertical both sides milling

[0072] RJ - radius of cutouts resulting from radial vertical both sides milling

[0073] RT - direction of the radius of the horizontal arc of the railway track

[0074] 17 - radially horizontally milled railway rail

[0075] 18 - simplified cross-section of the radially horizontally milled railway rail made outside the milling area, i.e., in the axis of symmetry of the railway sleeper 27

[0076] 27 - railway sleeper for rail 17

[0077] F7 - axis of symmetry of the railway sleeper 27

[0078] S7 - gauge of railway sleepers 27 in the axes of symmetry F7

[0079] 37 - arc-shaped surface formed as a result of a radial cutting with the radius RP

[0080] 47 - head of a radially horizontally milled rail

[0081] 57 - neck of a radially horizontally milled rail

[0082] 67 - foot of a radially horizontally milled rail

[0083] C7 - C7 characteristic cross-section of a horizontally and radially milled rail D7 - D7 characteristic cross-section of a radially horizontally milled rail

[0084] E7 - E7 characteristic cross-section of a radially horizontally milled rail

[0085] H - minimum height of the rail neck in the area of horizontal milling h - height of rail neck beyond the area of horizontal radial milling K7 - amount of one sided excess (overhang) of the rail foot from the railway sleeper

[0086] P7 - width of the railway sleeper for the radially horizontally milled rail

[0087] RP - radius of the cutout resulting from radial horizontal milling

Claims

Claims1. A railway track with straight sections (1), transition curves sections (2) and arc-shaped sections (3) comprising a ballast layer on which railway sleepers are laid out on which the rails are mounted characterized in that radially milled rails are placed on straight sections (1), movable railway sleepers and vertically on one side milled rails are placed on the transition curves sections (2) and on the arc- shaped sections (3).

2. Railway track according to claim 1 characterized in that the radially milled rails constitute radially vertically on both sides milled rails or radially horizontally on both sides milled rails.

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