Rail Fish Plate Dimensions: Complete Size Chart for UIC, AREMA and BS Rails

Rail fish plate dimensions are always matched to the rail profile they join, not chosen as a standalone size. A fish plate is specified by its length, the number and diameter of bolt holes, the hole spacing, and the section profile that matches the rail web and foot. UIC, AREMA and BS systems each define their own fish plate dimensions, and a plate made for one system will not fit another. The right way to order is to name the rail profile, the standard and the drilling pattern together.

A Fish Plate Is Matched to a Rail, Not a Number

If you have ever looked for a “standard fish plate size” and found a list of numbers that do not quite add up, you have hit the real problem with fish plate dimensions. A fish plate is not a bolt or a washer with a single standard size. It is a component matched to a specific rail profile.

At first glance, a size chart should settle it.

In practice, rail fish plate dimensions are not quite that straightforward.

The plate has to match the web and foot of the rail it joins. Its length, its bolt holes, its hole spacing and its section profile are all defined by the rail and the standard the rail belongs to. A UIC60 fish plate fits a UIC60 rail. A 136RE fish plate fits a 136RE rail. Swap them, and the joint does not work.

So what are the actual rail fish plate dimensions for UIC, AREMA and BS systems, and how do you read them?

What a Fish Plate Dimension Actually Specifies

A fish plate, also called a rail joint bar or splice bar, is the steel bar bolted across the ends of two rails to join them. Its dimensions are not arbitrary. Each one has a job.

Length. The plate spans the joint, long enough to bridge the rail ends and carry the bending load across the gap. Longer plates, often six-hole designs, carry more of the joint load.

Bolt holes. The number of holes, usually four or six, sets how many fish bolts hold the joint. More holes distribute the load over more bolts.

Hole diameter and spacing. The hole size must match the fish bolts, and the spacing must match the drilling pattern of the rail. If the holes do not line up with the rail, the bolts cannot go through.

Section profile. The plate’s cross-section matches the web and foot of the specific rail. This is the part that makes fish plates non-interchangeable between rail systems.

The practical point is that rail fish plate dimensions are always “the dimensions of the fish plate for rail X”. The rail is the reference. The plate follows it.

UIC Fish Plate Dimensions

UIC rail fish plate dimensions follow the UIC 864 leaflet and are matched to UIC rail profiles, the most common being UIC54 and UIC60.

For UIC60 rail, a typical four-hole fish plate is around 630 mm long, with bolt holes around 26 mm in diameter. A UIC54 plate is lighter and shorter, and six-hole designs run longer, around 800 mm, to carry more load across the joint.

The material is commonly a carbon steel grade selected for strength and fatigue resistance, and the plate is matched to the UIC60 or UIC54 rail foot geometry.

The key thing to remember is that the UIC designation names the rail, not the plate size. A “UIC60 fish plate” means “the fish plate that fits UIC60 rail”, and its dimensions follow from that rail’s profile.

AREMA Fish Plate Dimensions

AREMA rail fish plate dimensions follow the AREMA manual and are matched to North American rail sections, the most common being 115RE and 132-136RE.

In the AREMA system, fish plate length is often stated in inches, and hole count is part of the designation. A 115RE fish plate comes in four-hole and six-hole versions, with the four-hole plate around 24 inches and the six-hole plate around 36 inches long. The 132-136RE plates follow the same pattern, sized up for the heavier rail.

The material is carbon steel, and the plate section is matched to the RE rail profile, which has a different web and foot geometry from the UIC profiles.

This is the same principle as the UIC system: the RE number names the rail, and the fish plate dimensions follow the rail.

BS Fish Plate Dimensions

BS rail fish plate dimensions follow the British Standard, often BS 47-1, and are matched to BS rail sections such as BS75R, BS80A, BS90A and BS100A.

The dimensions vary with the rail section. A BS90A fish plate, for example, is commonly made in a four-hole configuration with a length in the region of 686 mm and bolt holes around 26 mm. Other BS sections have their own plates, each matched to its rail.

BS rail sections are less common than they once were, but they still appear in projects in the UK, the Middle East and Africa, which is why the dimensions still matter for replacement work.

Why the Profile Match Matters More Than the Size

Here is the point that ties the three systems together: the fish plate has to match the rail profile, and the profile is different in each system.

A UIC60 rail has a foot geometry that is different from a 136RE rail, even though both are “60-ish” rails by weight. A fish plate made for one will not seat correctly on the other, because the web height, the foot angle and the section shape are different.

The bolt holes make this concrete. The drilling pattern of a UIC60 rail is different from a 136RE rail, and the fish plate holes must line up with the rail holes. If they do not, the bolts cannot go through, and the joint cannot be assembled.

This is why the size chart only works when you already know the rail. Our guide to railway rail specifications covers how the rail profile and the drilling pattern are specified together, and our guide to UIC60 vs 136RE rail shows just how different two “similar” profiles can be.

What Should You Check Before Ordering Fish Plates?

When ordering fish plates, the dimensions are the second question. The first question is the rail.

Check	Why It Matters
Which rail profile?	The plate section must match the rail web and foot
Which standard?	UIC 864, AREMA or BS defines the dimensions
How many holes?	Four or six, matching the joint design
What hole diameter and spacing?	Must match the rail drilling and the fish bolts
What material and heat treatment?	Strength and fatigue resistance depend on it
What is the bolt size?	The holes must match the bolts

These are starting points, not a universal specification. The final check is always against the applicable standard and the specific rail.

Imagine two fish plates side by side. One is a UIC60 plate, the other a 136RE plate. They are roughly the same length and both have six holes. But the section that wraps the rail foot is different, and the hole spacing is different. One will seat on its rail. The other will not. The dimensions on paper are only useful when they are read against the right rail.

The Bottom Line on Rail Fish Plate Dimensions

A fish plate dimension is not a universal number. It is the dimension of the plate for a specific rail, under a specific standard, with a specific drilling pattern. UIC, AREMA and BS each define their own, and they do not interchange.

That is why I would not recommend ordering fish plates by size alone. Start with the rail profile and the standard. Check the hole count, the diameter and the spacing. Confirm the material. Then order the plate that matches the rail you actually have. That is the only way rail fish plate dimensions become reliable.

At Luoyang Fonyo Heavy Industries Co., Ltd., we manufacture fish plates and fish bolts matched to UIC, AREMA and BS rail profiles and drilling patterns. For any fish plate requirement, our engineering team can review the rail profile, standard, hole pattern and material before production.

If you have a rail drawing, a fish plate sample or an existing specification, send us the details. Our engineering team can help check the required fish plate dimensions, standard and compatibility before quotation.

---

FAQ About Rail Fish Plate Dimensions

What size is a standard fish plate?

There is no single standard size. A fish plate is matched to the rail profile it joins. A UIC60 plate is around 630 mm long for a four-hole design, while an AREMA 115RE four-hole plate is around 24 inches long. The size always follows the rail.

What is the difference between a UIC and AREMA fish plate?

They are matched to different rail profiles. UIC plates fit UIC rails with their web and foot geometry, while AREMA plates fit RE rails with different geometry and different drilling patterns. They do not interchange.

How many bolt holes does a fish plate have?

Commonly four or six. Four-hole plates are used for lighter joints, and six-hole plates are longer and carry more load across the joint. The number follows the joint design and the standard.

What material is a fish plate made of?

Fish plates are usually made of carbon steel, selected for strength and fatigue resistance, with a heat treatment suited to the joint. The specific grade depends on the standard and the application.

Can I use a fish plate from one rail system on another?

No. The plate section and the bolt hole spacing must match the specific rail. A UIC60 plate will not fit a 136RE rail, and the reverse is also true.

How do I know which fish plate to order?

Name the rail profile, the standard (UIC 864, AREMA or BS), the number of holes, and the drilling pattern. The plate dimensions then follow the rail.

Why do fish plate dimensions matter for safety?

The fish plate carries the bending load across the rail joint, which is the weakest point in the track. A plate that does not match the rail can seat poorly, concentrate stress and fail early.