Railway Fishplates Used in Indian Railway Tracks

In railway terms, fishplate, also named splice bar or joint bar, is a steel bar bolted to the ends of two rails to join them together in a track. It is a kind of rail-to-rail fastenings. 

As we know, the purpose of using fittings and fastenings in railway tracks is to hold the rails in their proper position in order to ensure the smooth running of trains. Until they serve their purpose well the tracks cannot maintain the level, alignment, and gauge within permissible limits even during the passage of trains. Thus, we can say that the function of a fish plate is to hold two rails together in both the horizontal and vertical planes.

IRS T-1/57 is the designation number of fishplates in the overall technical grocery of Indian railway. 

The fishplate steel in India shall have a minimum tensile strength of 5.58-6.51 t/cm2 and a minimum elongation of 20%. A fishplate must be designed to be the same strength as rail section. The strength of fishplate is less than that of the rail section, about 55%. So when we are using two fishplates, they are more than 100 % strength of the rail sections.

In India, the fishplate is usually divided into four categories as follows:

• A. Standard fishplate
• B. Joggled fishplate
• C. Special fishplate 
• D. Combination fishplate

I. Standard fishplate

The standard fishplate is generally in use. It is the channel shape like the letter C.  There are two holes on the either of the side of the rail joint. There are two fishplates and four bolts and four nuts at one joint. 

According to Indian Railways Specification (IRS T-1/57), a fishplate shall be manufactured using a special type of steel with composition given below:

• a. Carbon: 0.30–0.42%
• b. Manganese: not more than 0.6%
• c. Silicon: not more than 0.15%
• d. Sulphur and phosphorous: not more than 0.06%

Table Details of Standard Fishplates

Rail section	Drawing number	Weight per pair (kg)	Total length of fish plate [mm (in.)]	Length from centre to centre of hole [mm (in.)]	Diameterof fish bolt holes (mm)
52kg	090M	28.71	610(24)	166(6.5)	27
90R	071M	26.11	610(24)	166(6.5)	27
90R	059M	19.54	460(18)	114(4.5)	27
75R	060M	13.58	420(16.5)	102(4)	27
60R	961M	9.98	410(16)	102(4)	24
50R	1898M	8.31	410(16)	102(4)	20

II. Joggled fishplate

Joggled fishplate is commonly applied for connecting two rail tracks together of same or different sections to provide emergency repairs to broken welded rail or fractured rail section. In addition, it has wide uses in areas where the welded joints are fractured or have been defective. As an emergency clamp, it enables fast and temporary repair allowing continuous movements through the section at reduced line speed. The forged and machined joggled fishplate is very useful in broken welded rail or fractured rail sections.

Joggled Fishplate for 60kg	T-5849	Clamp for Joggled Fishplate for 60kg	T-4016
Joggled Fishplate for 52kg	T-5848	Clamp for Joggled Fishplate for 52kg	T-5551
Joggled Fishplate for 52kg (1 MTR. LONG)	T-5915
Joggled Fishplate for 60kg (1 MTR. LONG)	T-5916

III. Special fishplate 

The track portion to be detected has to be electrically isolated from adjoining rails so as to block the track circuit current, within its boundaries by providing Insulated rail joints or Block joints at each end of track circuit. In general Insulated rail joints or Block joints are required at the boundaries of the track circuit and at point & crossings where the polarity of track circuit is to be changed.

There are three types of insulated rail joints or block joints that are presently in use as given below:

1.  Insulated rail joint class "A"—these Insulation joints are made of special type of wood and used in yards where speed of train is slow.
2.  Insulated rail joint class "B"—these Insulation rail joints are made up of Nylon 66. These are also called Nylon insulated rail joint.
3.  Insulated rail joint class "C"—these are also called as glued insulated rail joints. Glued insulated rail joints. These are mostly used in main line for high speed trains. The glued joints are being increasingly provided on railways to avoid failures of insulation joints particularly in long welded rails. There are two types of glued joints: G3 (L) type - six bolts, G3 (S) type - four bolts

IV. Combination fishplate

Combination fishplate is used to connect rails of two differential rail sections. The design is to cover the rail section at either end adequately up to the point in the centre where the rail section changes. Another design feature is the elimination of the expansion gap to give them more strength. The varying depths of the combination fishplates can be used in the rail sections, for example, 52 kg/90 R, 90 R/75 R, 75 R/60 R, etc., which provides a common top table for the two rail sections they join. 

When we are using two different rail sections obviously, there is going to be a difference in the sectional area as well as the sectional weight of those rail sections. So in that sense one rail section which is having a lesser weight will be termed as a lighter rail another rail section will be termed as heavier rail. Based on the location of the lighter rail with respect to heavier rail, the fishplates are marked right in, right out, left in, and left out depending upon their positions. 

Combination Fishplate No.
50KG/90R	CSO-C-1900(M) &1901(M)
60KG/52KG	T-696 TO T-699
52KG/90BS	CSO-C-1944(M) &1945(M)
90R/90BS	T-10559 TO T-10560

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