DESC:FIELD OF INVENTION:

The present invention relates to a switch expansion joints (SEJ’s) for use in railway tracks particularly to rail expansion joint, known as Switch type-Switch expansion joints (SJSEJ) for use in railway tracks at the end of long welded rails fitted to the sleepers. The SJSEJ installed at either ends of LWR allows longitudinal movements owning to its special designs. The outer rail is the incoming LWR rail. The design of SJSEJ is based on firmness of housing of inner rails into outer rails and guarantees unhindered longitudinal movement of outer rail for depicting expansion and contraction of LWR.
The inner rail provides gauge face, housed in outer rail. The unified system of inner & outer rail along with their components lead to apportioning of load between inner and outer rail in an organized manner. There is neither any cut/groove on gauge face nor on non-gauge face in running rail for expansion arrangement i.e., gap for expansion & contraction. Switch Expansion Joint (SEJ) is used to take care of the expansion in a long welded rail and is placed at the either ends.
BACKGROUND OF THE INVENTION

A switch is a device that enables the train to change its track enabling it to proceed in the correct direction. SEJ is a device, installed at the end of LWR/CWR, to allow the longitudinal movements in the breathing length due to temperature variations as it is a device that compensates the natural changes in the track due to temperature variations and protects the technical standard dimension of the same.
In the prior art, earlier switch expansion joint comprised of one accomplice rail (herein known as tongue rail) along with the incoming main running rail (herein known as stock rail). For brevity, the side of the rail head which guides the wheel flange is called gauge face. In this said assembly, commonly known as Conventional SEJ, the incoming main rail (stock rail) involves cut followed by machined/bent portion of stock rail to accommodate the accomplice rail (tongue rail), after its cut & hugging with stock rail in its machined/bent portion. The tongue rail after the cut in stock rail forms the gauge face. On either side of the assembly of SEJ, the main running rail forms the gauge face to guide the wheel. The assembly at either end thus consist of pair of one Tongue rail & one stock rail on left hand side as well as on right hand side. These tongue rail & stock rail, bent & machined, cater for expansion of long rail.

Improved switch expansion joints (isej)

Later, a need of change /advancement was felt on to improve the service life of sej by introducing ‘improved switch expansion joint’ (isej) of which either of the tongue rails & stock rails were bend free. Improved sej (isej) of two designs, one with single gap of maximum 80 mm and another with double gaps of maximum 65 mm were adopted for regular use.

Single gap and double gap are being manufactured and laid on Indian railways.

Single gap isej
The design consists of three sections of rails, the tongue rail, stock rail and gap avoid rail. Both tongue rail as well as stock rails of 1200 mm and 1180 mm respectively are incoming running rails on either side of the assembly and are laid both for left hand and right hand. Gauge face of tongue rail and gauge face of stock rail are available, one by one, for the flange of wheel to negotiate these rails, for their respective lengths. Cut are provided on one extreme end of the assembly in the tongue rail and on other extreme end of the assembly in the stock rail on non-gauge face side followed by machined portion of 1200mm & 1180mm respectively. After the cuts, almost the entire length of the tongue rail and stock rail are machined on non-gauge face side. In between two cuts at the either ends of the assembly, the gap avoiding rail is placed against the stock rail and tongue rail on their non-gauge face side. Gauge face of tongue rails and stock rails is thus encountered by the flange of wheel to negotiate, opposite to the cut and machined portion provided in these two rails.

Double gap isej

The design consists of three sections of rails, two incoming tongue rails at either ends of long rail of around 610 mm each and in between these two tongue rails is placed as fabricated stock rail. Both tongue rail are incoming running rails on either side of the assembly and are laid both for left hand and right hand. Gauge face of both the incoming tongue rails and the gauge face of the fabricated stock rail provide, gauge face for the flange of wheel to negotiate in their respective lengths. Cuts are provided in the incoming tongue rails i.e. On the extreme end of the assembly in the tongue rails on non-gauge face side followed by machined portion of tongue rail on either ends for a length of 610mm. Gauge face of both the tongue.

Rails is thus encountered by the flange of wheel to negotiate, opposite to the cut and machined portion provided in these two rails.
In the prior art of conventional SEJ an assembly of two pairs was provided at
either end to cater for Longitudinal movement of rails due to temperature variation.

Each pair consisted of one tongue rail & one stock rail. Tongue rail & stock rail were bent and machined to cater for expansion of long rail. Tongue rail forms the gauge face, from the point of the cut and machined portion in stock rail.
In this sej of prior art, no fracture complained in tongue rail because no groove in tongue rail head at non-gauge face side while stock rail was having groove at gauge face. Stock rail got fractured at toe side, which was strengthened with rf strap on web of stock rail later.

Railway board ordered to stop procurement of both these ISEJS (single gap and double gap) because of fractures and unreliable designs.

Though these “Improved SEJ” (ISEJ’s) were considered to have definite advantages over the conventional SEJ due to no bends in stock and tongue, RDSO has taken note of many instances of crack/fracture of tongue and stock rails of improved sejs in field in service. The cases of loosening and breakage of HTS bolts used in fabrication of stock rail have also been reported since last many years.

Both these designs of ISEJ’s are sensitive to any situation which creates unwanted additional stress in cut and machined portion of tongue rail area on non-gauge face side due to indeterminate behavior of tongue rail & stock rail/gap avoid rail till end of tongue rail. This is likely to be more in case of single gap isej because of gap avoiding rail may not give that sound effect as fabricated rail in double gap ISEJ and further area of improper attention will be more in case of single gap ISEJ.

Thick Web SEJ

Lately, Railway board conveyed a desire to procure thick web SEJ for development/trial. Field observations reported are not very conducive for a wishful approach of this thick web SEJ to be acceptable. Some of the field observations are as under:-
1. Abnormal Length of Truncated Tongue Rail of the order of 544 mm (1’ 10”) in isolation without accomplice rail & bracket leading to severe hammering of wheel on tip of stock rail, Vertical wear of Stock Rail noticed at sleeper no. 3 where wheel load is transferred at SR,
2. Design ensure a very limited portion of both rails to work together because of clamping near ATS. Design defects on account of fragile stoppers in tongue rail, allows rubber pads under tongue rail to fall. Similarly, design defect on account of rubber pad provided under stock rail without collar on one side resulting in tendency for rotation of rubber pad under stock rail.
3. Physical smooth execution for retentivity of clamping portion near ATS is not possible.
4. Wear measurement for stock rail and tongue rail is not possible at sleeper 3-10 as TR & SR in closed position tightened with safety clamp.

Behavior of SEJ structure of thick web SEJ as a whole including components thus suffer/inherits flaws.
DESCRIPTION OF THE INVENTION
The basic concept of the design switch type switch expansion joints (SJSEJ) is based on firmness of housing of inner rails into outer rails and there by the stability & behaviour of SJSEJ structure and its components is ensured in an organised manner . No unwanted issue is contemplated. There is neither any cut/groove on gauge face nor on non-gauge face in running rails of 60 kg UIC for expansion arrangement i.e., gap for expansion & contraction.
Structure of SJSEJ: -
The SJSEJ structure consists of:
(i) outer rail (3& 4) is the incoming LWR rail. The design of SJSEJ guarantees unhindered longitudinal movement of outer rail for depicting expansion and contraction of LWR (14).
(ii) inner rail (1 & 2) provides gauge face, housed in outer rail till the inner running rail is fully capable of taking full load.
(iii) unified system of inner & outer rail along with their components, lead to apportioning of load between inner and outer rail in a defined manner.
(iv) for each side Left Hand/Right Hand combination of inner rail & outer rail has been picked up in a manner to ensure smooth steering of rolling stock without jerking creating any unwanted issues on SJSEJ structure and its components. Besides this, the combination of inner & outer also facilitates necessary machining for the assembly to work in unified manner and also facilitates diverging of outer rail, once apportioning load is no more required.
(v) The replica of this arrangement continues for LH/RH, thus constituting/comprising of 4 combination of inner rail & outer rail- 2 RH& 2 LH for a pair of assembly as (1,2 & 3, 4).
Inner rail, its machining, its components, its fixity and behavior: -
Machining of inner rail:
Inner rail (1) is machined heavily in a manner that when the wheel presses the incoming rail of LWR (3) ( i.e.outer rail of SJSEJ structure), the wheel instantly can move from outer to inner rail of SJSEJ without hitting the tip of inner rail (1) on shifting of gauge face from incoming LWR to inner rail (1).
The width of tip of head of inner rail is 6mm and is fully machined over its entire length except small portion in centre. The part of this length, the head width varies from 6mm to full head width.
Commensurate with the centre line of web, the web fit brackets(11) are provided with bolts (9) at every sleeper throughout the entire length, ensuring the fixity of inner rail & making it immobile.
The incoming rail from LWR (3), (henceforth outer rail of SJSEJ structure) starts bending /diverting from the point of commencement of housing of inner rail (1, 2) at head and foot. The bending of outer rail follows the similar curvature of machined inner rail. The outer rail thus accommodates/houses the inner rail as per the curvature of the former.
Fixity of inner rail:
The head and foot of inner rail (1,2) is completely housing and resting on outer rail (3,4) combinedly ensures availability of head width to be never less than full head of normal rail of 60 kg UIC. The process of inner rail gradually developing into full rail with complete head and complete foot establishes fixity of inner rail as elaborated below:
Housing of head
The preparation of housing of inner rail (1,2) involves, starting of machining in the incoming LWR rail (3, 4) with similar slope on non-gauge face side of inner rail and gauge face side of outer rail till the head width of inner rail is restored. This matching of head because of side slope initiates perfect housing.
Housing of foot of inner rail
The entire foot of inner rail is in three parts: fully cutted foot, followed by undercut portion housed on foot of outer rail and remaining width of full foot resting on bearing plate.
The diverted length of outer rail along the Left Hand/Right Hand curvature of inner rail results in shaping of inner rail to be over-riding in nature on the outer rail.
Finally, web fit brackets(11) play the role of icing on cake for guarantying fixity of inner rail (1,2) in true sense. These are placed on every sleeper along the center line of web of inner rail ensures fixity and integrity of gauge face of inner rail though bolting these brackets which are welded on base plate (5) of bearing plate are fixed with sleeper via bolting (9).

Description of fixtures: -
Web fit bracket (11) bolted (9) with inner rail (1&2) and ZTLF (7) partially/laterally clamping the outer rail (3,4) is welded to the base plate (5).This base plate is in turn tightened with plate screws (13) at every sleeper. This bracket (11) web fitted with the inner rail, ensures building up the head width to full head width with curvature in conformity with the curvature of outer rail. This necessary curvature on inner rail and outer rail facilitates the housing/unifying both the rails. System of SJSEJ unifying both inner rail(1,2) and outer (3,4) ensures the availability of full head width of normal rail all through.
While the ZTLF (7) provides the unhindered longitudinal movement to the outer rail (3 & 4)/LWR.
This entire system of working in unison of SJSEJ resting on 14 mm MS base plate (5). The vibrations coming on the unified assembly are getting absorbed by the 6 mm rubber pad (6) provided underneath the base plate (5).
The entire system working in unison involves: -
(a) Web fit brackets(11) provided with bolts in every sleeper throughout the entire length of inner rail (1 & 2) ensuring the fixity of inner rail (1,2). These brackets being web fit, their distance keep on varying as the head width of inner rail keeps on increasing from 6mm to full head width while keeping the gauge face straight.

(b) face plate(12):- web fit brackets (11) are welded on face plate which is of 18-20 mm thick. The width of the face plate for the inner rail keeps on increasing to accommodate the increasing width of foot of inner running rail (1 & 2) on gauge face till the under cutting of foot is complete.

(c) ZTLF(7): - the base plate portion of the outer rail is provided with the 10mm thick rubber pad(8), which is both side colored. ZTLF as usual is provided with 2mm steal embedded ss plate to provide frictionless movement of the outer rail (3 & 4). ZTLF(7) allows the outer rail to move laterally/free lateral movement while providing enough and equal toe load when extra (vertical/lateral/any kind of load) is exerted on outer rail.

Benefits of the present invention:
A. On account of firm housing of inner rail & outer rail in SJSEJ with both inner and outer rail to be of 60 kg UIC Rails.

The manner in which fixity of inner rail (1,2) is ensured as above for the entire length while both inner and outer rail to be of 60 kg UIC Rails, the system results in firm gripping of inner rail with outer rail, the outcome of which is unison to perform together by inner rail and outer rail. This result:

(i) The head and foot of inner rail(1,2) is completely housing and resting on outer rail (3,4) combinedly ensures availability of head width to be never less than full head of normal rail of 60 kg UIC.

(ii) The wheel instantly moves from outer (3 , 4) to inner rail without hitting tip of inner rail and thus no jerking action on shifting of gauge face from incoming LWR to inner rail.

(iii) Both inner rail & outer rail perform simultaneously in unison for apportioning load amongst themselves because of firm gripping on account of various support systems. This apportioning of load continues in an unified manner till the requirement of inner rail is fully met to share the load independently which happens when the head of the inner rail is complete to full head width and outer rail thereafter continues to depict unhindered longitudinal movement of LWR.

(iv) The unified behavior of SJSEJ structure suitably makes possible to use ZTLF (7) for ensuring the longitudinal movement accrued in the incoming rail of LWR (3,4 ).

(v) The fixture system as noted above, consist of web fit brackets(11) for bolting inner rail and thus ensuring the inner rail blocking & making the inner rail immobile. The brackets are welded on the bearing plates (12) which provides the base for the (ZTLF ) for outer rail. Thus the fastening system involves ZTLF on the outer side of the outer rail (3,4). Inner side of the outer rail (3,4) is laterally fixed by the foot of the inner rail till the undercutting of inner rail is over. This is overriding of inner rail over outer rail.
(vi) The impact made by overriding of inner rail (1,2) on outer rail (3,4) continues to be sustainable to make SJSEJ a homogeneous/monolithic by providing web fit bracket on the gauge face side of the inner rail. The necessity for arriving at both inner and outer rail to work in unison i.e to have monolithic behavior removes the drawbacks of non-monolithic behavior of tongue rail and stock rail in SEJ under trial with thick web tongue rail as well as ISEJs.
(vii) The privilege offered by inner and outer rail to perform together continues to ensure both inner and outer rail to apportion the vertical load as a single unit in unison.

B. Benefits of present invention are listed while both inner and outer rails to be of 60 kg UIC.

(i) The inner running rail (1,2) is thoroughly bolted on at every sleeper, fastening it with sleeper and outer running rail (3,4) by a single bearing plate (at every sleeper) making it single robust system. The same type of bolting was never possible in single gap ISEJ or double gap ISEJ.

(ii) There is no any design arc or cut either on the gauge face side or at non-gauge face side, thus chance of any kind of jumping get totally in eliminated unlike in all previous SEJ’s designs.

(iii) There is no point in SJSEJ where continuity on gauge face for the wheel tyre is disrupted. The continuity is always maintained making it more or less similar to LWR.

(iv) There is no any direct impact of lateral load on any of the rails, be it outer running rail (3,4) or inner running rail (1,2) as the load gradually transfers from outer running rail to inner running rail is well defined and established.

(v) Since there is no single machined rail or truncated rails between any two sleepers, the vertical dancing gets totally eliminated unlike in single gap and double gap ISEJ.

(vi) Since the expansion and contraction in SJSEJ is in outer running rail which does not falls in loop with inner running rail, no special attention of maintenance is required.

(vii) At no point in SJSEJ wheel tire gets rail head width of less than 72 mm, which ensures uniform load at every given point like LWR.

(viii) The complete arrestment of inner running rail (1,2) housed inside outer running rail (3,4) fastened with bearing plated (5-13) eliminates any kind of vibrations, deflection, twisting and lateral deflection, makes the system maintenance free.

(ix) ZTLF (7) fastening for outer running rail (3,4) making latitudinal movement hindrance free and keeping the structure well within defined area/bearing plate (5-13) makes the system well defined and any unwanted forces to act or create.
The present invention SJSEJ essentially comprises of the following items:

1. Inner rail L.H
2. Inner rail R.H
3. Outer rail L.H
4. Outer rail R.H
5. Base plate
6. Rubber Pad 6mm
7. ZTLF
8. 10 mm Grooved Rubber pad with 2 mm S.S Plate embedded
9. Bolt with Nut
10. Spring Washer
11. Bracket with Ribs
12. Face Plate
13. Plate screw
14. Expansion/contraction zone for outer rail
BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail with reference to the drawings accompanying the specification, wherein-

Fig.1 shows the fixing/laying of inner rail with outer rail on sleepers with expansion and contraction zone for outer rails.
Fig.2 shows the assembly of inner rail, outer rail, bracket, bolt, rubber pad, ZTLF on one sleeper at junction of head.
Fig. 3 shows canting of outer and inner rails at the start of housing of inner rail.
Fig.4 shows canting of outer and inner rail at the point of full head width of inner rail.

DETAILED DESCRIPTION OF DRAWINGS

Fig.1 shows outer and inner rail assembly with expansion and contraction zones. The Inner rail (1,2) is machined heavily in a manner that when the wheel presses the incoming rail of LWR (3,4) ( i.e.outer rail of SJSEJ structure), the wheel instantly can move from outer to inner rail of SJSEJ without hitting the tip of inner rail (1,2) while shifting gauge face from incoming LWR to inner rail (1,2) alongwith unhindered longitudinal movement of outer rail for expansion and contraction of LWR (14).
Fig.2 shows a Switch type canted-Switch expansion joints(SJSEJ) at the Junction of head of outer and inner rail. The figure shows a web fit bracket (11) fixed with nut and bolt (9) along with sealing ring (10) with inner rail (1&2) and Zero toe load fastening (ZTLF) (7) having 10mm rubber pad(8) partially/laterally clamping the outer rail ( 3,4) is welded to the face plate (12).This face plate is welded to the base plate (5) which in turn tightened with plate screws (13) at every sleeper. The base plate (5) while resting on sleeper is provided with 6 mm rubber pad (6) beneath the base plate. This bracket (11) web fitted with the inner rail , ensures building up the head width to full head width with curvature in conformity with the curvature of outer rail.

Fig. 3 shows canting of outer and inner rails at the start of housing of inner rail as per canted/ inclined profile of sleeper.

Fig.4 shows canting of outer and inner rail at the point of full head width of inner rail as per canted/inclined profile of sleeper.
,CLAIMS:We Claim:
1. A switch expansion joint for railway tracks without any cut on gauge face or non gauge face gripping firmly the inner rail(1,2) and outer rail (3,4) so as to perform simultaneously in unison with head and foot of inner rail (1,2) completely housing and resting in outer rail(3,4) where both inner rail and outer rail are of similar standard rail of conventional type, apportioning load over the full head width as of normal rail ensuring unhindered longitudinal movement of incoming LWR rail/outer rail(3,4) for expansion and contraction of long welded rail(14), wherein the inner rail(1) is machined to be housed inside the outer rail in a manner that when the wheel presses the incoming rail of long welded rail (3,4), the wheel instantly adapted to move from outer to inner rail of switch-type switch expansion joints(SJSEJ) without hitting the tip of inner rail (1,2) while shifting gauge face from incoming long welded rail(LWR) to inner rail (1,2) , wherein fixtures makes the inner rail immobile, ensuring smooth steering of rolling stock without jerk or creating any unwanted issues on switch expansion joints structure and its components, diverging of outer rail in absence of load, allowing its longitudinal movement by provision of zero toe load fastening(ZTLF) (7) on same base plate (5)thereby eliminating any kind of vibrations, deflection, twisting and lateral deflection, making the system maintenance free.
2. A switch expansion joints as claimed in claim 1, wherein the fixtures are web fit brackets (11) provided with bolts (9) at every sleeper throughout the entire length, ensuring the fixity of inner rail & making it immobile and commensurating it with the centre line of web of inner rail.
3. A switch expansion joints as claimed in claim 1, wherein the incoming LWR rail is the outer rail and both the inner and outer rail are preferably of 60kg UIC.
4. A switch expansion joints as claimed in claim 1, wherein replica of this arrangement continues for LH/RH, thus constituting of 4 combination of inner rail & outer rail- 2 RH& 2 LH for a pair of assembly as (1,3 & 2, 4) and thus providing gap for expansion and contraction of 2 different LWR’s.
5. A switch expansion joints as claimed in claim 1, wherein the inner rail head width varies from 6mm to full head width as of normal rail except a shorter portion in centre.
6.A switch expansion joints as claimed in claim 1, wherein the brackets (11) are welded on the bearing plates (12) which also provides the base for the ZTLF for outer rail.
7. A switch expansion joints as claimed in claim 1, wherein the fastening system involves ZTLF on the outer side of the outer rail (3,4) and the Inner side of the outer rail (3,4) is laterally fixed by the foot of the inner rail till the undercutting of inner rail is over to accomplish overriding of inner rail over outer rail.
8. A switch expansion joints as claimed in claim 1, wherein overriding of inner rail (1,2) on outer rail (3,4) continues to be sustainable to make switch expansion joints a homogeneous/monolithic by providing web fit bracket on the gauge face side of the inner rail.
9. A switch expansion joints as claimed in claim 1, wherein inner running rail (1,2) is all through bolted to bracket which is also bolted to sleeper via base plate and further outer running rails (3,4) foot are also arrested by ZTLF by the same bearing plate at every sleeper making it single robust system.
10. A switch expansion joints as claimed in claim 1, wherein ZTLF (7) fastening for outer running rail (3,4) makes longitudinal movement hindrance free and keeping the structure well within defined area/bearing plate (5-13).
11. A switch expansion joints as claimed in claim 1, wherein continuity of gauge face is not disrupted for the wheel tyre hence jumping of wheel tyre gets totally eliminated.
12. A process for manufacturing a SEJ for railway tracks without any cut on gauge face or non-gauge face of inner rail and outer rail to perform in unison comprises the steps of:
-machining of inner rail and outer rail,
-housing of head and foot of rail into outer rail to over ride on the outer rail,
-fixing inner rails with web fit brackets (11) making it immobile and outer rail with ZTLF for making unhindered longitudinal movement of incoming long welded rail(LWR).

Dated this 13th day of July, 2022

(M. P. Bhatnagar)
IN/PA-168
Bhatnagar & Associates
Agent for the applicant