Understanding the precise dimensions of railroad tracks is critical for railway engineering, maintenance, and procurement. This guide details the specific measurements, weights, and profiles of various rail sections used globally, alongside the essential specifications for rail clips that secure them.
Standard Dimensions of Railroad Tracks for ASCE Sections
The American Society of Civil Engineers (ASCE) established some of the earliest standards for rail profiles in North America. These sections are still widely used in industrial applications, crane runways, and light rail systems. The dimensions of railroad tracks under ASCE standards maintain a specific ratio of weight distribution between the head, web, and base.
ASCE Rail Profile Specifications
The following table outlines the key dimensional data for common ASCE rail sections. All measurements are in inches unless otherwise noted.
|
Nominal Weight (lb/yd) |
Rail Height |
Base Width |
Head Width |
Web Thickness |
Section Number |
|
12 lb |
2.00 |
2.00 |
1.00 |
3/16 |
1240 |
|
16 lb |
2.375 (2 3/8) |
2.375 (2 3/8) |
1.172 |
7/32 |
1640 |
|
20 lb |
2.625 (2 5/8) |
2.625 (2 5/8) |
1.344 |
1/4 |
2040 |
|
25 lb |
2.75 (2 3/4) |
2.75 (2 3/4) |
1.50 |
19/64 |
2540 |
|
30 lb |
3.125 (3 1/8) |
3.125 (3 1/8) |
1.688 |
21/64 |
3040 |
|
40 lb |
3.50 (3 1/2) |
3.50 (3 1/2) |
1.875 |
25/64 |
4040 |
|
60 lb |
4.25 (4 1/4) |
4.25 (4 1/4) |
2.375 |
31/64 |
6040 |
|
80 lb |
5.00 |
5.00 |
2.50 |
35/64 |
8040 |
|
85 lb |
5.188 (5 3/16) |
5.188 (5 3/16) |
2.563 |
9/16 |
8540 |
The dimensions of railroad tracks in the ASCE series often feature equal height and base width measurements, particularly in lighter sections up to 80 lbs. This symmetry was a hallmark of early design to simplify manufacturing and tie plate compatibility.
AREA and AREMA Rail Dimensions
Modern main line operations typically utilize heavier rail sections defined by the American Railway Engineering Association (AREA), now AREMA. These profiles are designed to withstand heavier axle loads and higher speeds. The dimensions of railroad tracks in this category prioritize a thicker web and a deeper head to accommodate wear.
Heavy Rail Specifications
Standard heavy rail sections used in North American freight and passenger lines include the 115 RE, 132 RE, and 136 RE profiles.
|
Rail Section |
Nominal Weight (lb/yd) |
Height (in) |
Base Width (in) |
Head Width (in) |
Web Thickness (in) |
|
90 RA (ARA-A) |
90.0 |
5.625 |
5.125 |
2.563 |
0.563 |
|
100 RE |
101.5 |
6.00 |
5.375 |
2.688 |
0.563 |
|
115 RE |
114.7 |
6.625 |
5.50 |
2.719 |
0.625 |
|
132 RE |
132.1 |
7.125 |
6.00 |
3.00 |
0.656 |
|
136 RE |
136.2 |
7.313 |
6.00 |
2.938 |
0.688 |
|
141 AB |
141.0 |
7.313 |
6.00 |
3.00 |
0.750 |
When analyzing the dimensions of railroad tracks for heavy haulage, the moment of inertia becomes a critical factor. For example, the 136 RE rail offers significantly greater resistance to bending compared to the 115 RE, making it suitable for unit trains carrying coal or ore. The increased height and web thickness contribute directly to vertical stability.
European Standard (EN) Rail Dimensions
European railways utilize the EN 13674-1 standard, which classifies rails by mass per meter (kg/m) rather than pounds per yard. The dimensions of railroad tracks in Europe differ slightly in profile geometry, often featuring a broader head profile relative to height.
Common EN Rail Profiles
The UIC 60 (60E1) and UIC 54 (54E1) are the standard rails for high-speed and mixed-traffic lines across Europe.
|
Rail Profile |
Weight (kg/m) |
Height (mm) |
Base Width (mm) |
Head Width (mm) |
Web Thickness (mm) |
|
60E1 (UIC 60) |
60.21 |
172.0 |
150.0 |
72.0 |
16.5 |
|
54E1 (UIC 54) |
54.77 |
159.0 |
140.0 |
70.0 |
16.0 |
|
50E6 (U 50) |
50.90 |
153.0 |
140.0 |
65.0 |
15.5 |
|
49E1 (S 49) |
49.39 |
149.0 |
125.0 |
67.0 |
14.0 |
Engineers must convert these metric dimensions of railroad tracks carefully when integrating European rolling stock or maintenance equipment on non-metric infrastructure. The 60E1 profile is particularly robust, designed to handle the dynamic forces of high-speed trains like the TGV and ICE.
Crane Rail Dimensions and Profiles
Crane rails differ from standard transport rails as they are designed to support massive point loads at slower speeds. The dimensions of railroad tracks for cranes typically feature a very wide head to maximize the contact area with the crane wheel, reducing contact stress.
DIN and American Crane Rail Specs
Crane rails are often specified under DIN (German) or American standards. The profiles are squat, with thick webs to prevent buckling under heavy vertical loads.
|
Rail Type |
Weight (kg/m) |
Height (mm) |
Base Width (mm) |
Head Width (mm) |
Web Thickness (mm) |
|
A45 |
22.1 |
55 |
125 |
45 |
24 |
|
A55 |
31.8 |
65 |
150 |
55 |
31 |
|
A75 |
56.2 |
85 |
200 |
75 |
45 |
|
A100 |
74.3 |
95 |
200 |
100 |
60 |
|
A120 |
100.0 |
105 |
220 |
120 |
72 |
|
CR 104 |
51.6 |
127 (5 in) |
127 (5 in) |
63.5 (2.5 in) |
25.4 (1 in) |
|
CR 175 |
86.8 |
152.4 (6 in) |
152.4 (6 in) |
107.9 (4.25 in) |
38.1 (1.5 in) |
The dimensions of railroad tracks for crane applications like the A120 show a significant deviation from standard tee rails, with base widths often exceeding the rail height. This low center of gravity ensures stability against lateral forces exerted during crane operation.
Importance of Accurate Rail Dimensions
The dimensions of railroad tracks dictate the compatibility of all other track components. A mismatch in head width can lead to uneven wheel wear, while incorrect base width specifications can prevent rail clips and tie plates from seating correctly. Regular measurement of dimensions of railroad tracks is essential for identifying wear patterns such as head loss or gauge corner wear. Maintenance teams use profilometers to compare the current dimensions of railroad tracks against the original profile to determine when grinding or replacement is necessary.
Rail Clip Specifications and Dimensions
While the dimensions of railroad tracks provide the running surface, rail clips are the critical fasteners that hold the rail to the sleeper or base plate. Rail clips must maintain sufficient toe load (clamping force) to prevent rail rollover and longitudinal movement (creep) while accommodating the rail’s thermal expansion.
Types of Rail Clips
Rail clips are categorized based on their installation method and design flexibility.
- Bolted Clips: Secured via a bolt, nut, and washer assembly. These are common in industrial and crane rail applications where adjustability is required.
- Weldable Clips: The lower housing is welded to the steel support, and the upper clip is bolted down. This offers a permanent, high-strength bond.
- Elastic (Spring) Clips: Used extensively in modern concrete sleeper tracks (e.g., E-clips, SKL clips). They are driven into a shoulder cast into the sleeper and rely on spring tension.
Standard Rail Clip Dimensions
The selection of a rail clip depends directly on the dimensions of railroad tracks being secured, specifically the base width and thickness.
Adjustable Crane Rail Clips
These clips often feature a rubber “nose” that applies force to the rail foot, allowing for small lateral adjustments to correct gauge.
|
Clip Model |
Max Side Load (kN) |
Bolt Size |
Lateral Adjustment (mm) |
Weight (kg) |
Compatible Rail Base Widths |
|
Type 1116 |
45 |
M16 |
10 |
0.6 |
Up to 125mm |
|
Type 1216 |
75 |
M20 |
10 |
0.9 |
125mm – 150mm |
|
Type 1220 |
120 |
M24 |
15 |
1.4 |
150mm – 220mm |
|
Type 9120 |
200 |
M24 |
20 |
2.1 |
> 220mm |
Rigid Rail Clips (KPO Series)
KPO clips are rigid clips often used in industrial tracks and slab tracks. They do not offer the same elasticity as E-clips but provide immense holding power.
|
Clip Type |
Length (mm) |
Width (mm) |
Height (mm) |
Bolt Hole Diameter (mm) |
Weight (kg) |
|
KPO-3 |
130 |
60 |
28 |
22 |
0.6 |
|
KPO-6 |
140 |
65 |
32 |
24 |
0.8 |
|
KPO-9 |
160 |
70 |
36 |
24 |
1.1 |
Elastic E-Clip Specifications
E-Clips are manufactured from high-quality spring steel bars. The diameter of the bar and the geometry of the loops determine the clamping force.
|
Clip Model |
Bar Diameter (mm) |
Toe Load (kgf) |
Material Grade |
Hardness (HRC) |
Application |
|
E1609 |
16 |
750 – 900 |
60Si2Mn |
44-48 |
Light rail / Metro |
|
E1809 |
18 |
900 – 1100 |
60Si2Mn |
44-48 |
Standard Freight |
|
E2007 |
20 |
1200 – 1500 |
60Si2MnA |
44-48 |
Heavy Haul |
|
E2055 |
20 |
1200 – 1500 |
60Si2MnA |
44-48 |
Concrete Sleepers |
Rail Clip Materials and Manufacturing
Rail clips must withstand high-frequency vibrations and cyclical loading.
- Material: Most elastic clips are made from spring steel grades like 60Si2Mn or 38Si7. Rigid clips (like KPO) are often cast from carbon steel (Q235 or Q345) or ductile iron.
- Heat Treatment: Elastic clips undergo quenching and tempering to achieve the necessary fatigue resistance and hardness (typically 44-48 HRC).
- Surface Protection: To prevent corrosion, clips are treated with hot-dip galvanizing, sherardizing, or electrostatic coating.
Matching Clips to Dimensions of Railroad Tracks
Selecting the correct clip requires verifying the dimensions of railroad tracks at the foot.
- Toe Height: The clip must be designed for the specific thickness of the rail base at the toe. If the rail base is too thick, the clip will be overstressed during installation. If too thin, the clip will not generate sufficient clamping force.
- Insulators: In electrified tracks or signaling areas, electrical insulators are placed between the clip and the rail foot. The dimensions of railroad tracks must account for this additional thickness.
- Base Width: For bolted clips, the distance from the bolt hole to the rail edge is critical. If the dimensions of railroad tracks change (e.g., swapping 115 RE for 132 RE), the clip positioning or the clip type itself may need to be altered.
Detailed Specification of the 103 Rail Clip
The 103 rail clip is a specific type of rigid clip used for ASCE rails ranging from 55 lbs to 100 lbs.
- Material: Forged Steel
- Height: 0.75 inches
- Width: 2.5 inches
- Length: 2.0 inches
- Hole Type: Oval (1-1/16″ x 25/32″) allows for lateral adjustment.
- Weight: 0.75 lbs
- Compatible Rails: ASCE 60, 80, 85, 100 lb sections.
This clip is versatile because the oval hole accommodates slight variations in the dimensions of railroad tracks, simplifying installation on steel ties or base plates.
Installation Dimensions for Rail Clips
Proper installation ensures the clip functions as intended.
- Weldable Bases: The distance from the center of the rail to the weld seam of the clip base must be precise. This dimension is derived from the rail base width divided by two, plus the specific offset required by the clip manufacturer.
- Torque Specifications: For bolted clips, torque must be applied according to the bolt grade and diameter. Over-torquing can yield the bolt or crush the clip; under-torquing allows the rail to slip.
- M20 Bolt (Grade 8.8): Approx. 350-400 Nm.
- M24 Bolt (Grade 8.8): Approx. 600-650 Nm.
Relationship Between Track Geometry and Rail Dimensions
The dimensions of railroad tracks influence the overall track geometry, including gauge, superelevation, and alignment.
- Gauge Measurement: The standard gauge (1435mm or 4′ 8.5″) is measured 14mm (approx. 5/8″) below the top of the rail head. Therefore, the contour of the rail head—part of the dimensions of railroad tracks—is vital for accurate gauge measurement.
- Wear Limits: Maintenance standards specify maximum vertical and lateral wear limits based on the original dimensions of railroad tracks. For example, a 136 RE rail may have a vertical wear limit of 3/4 inch for Class 4 track. Once wear exceeds this dimension, the moment of inertia drops below the safety margin, requiring rail replacement.
FAQ: Rail Dimensions and Specifications
Q1: What is the standard width of a railroad track?
A1: The standard gauge (distance between inner rail heads) is 1,435 mm (4 ft 8 1/2 in). However, the “width” of the rail itself refers to the base width, which varies by profile, e.g., 6 inches for 136 RE rail or 150 mm for UIC 60 rail.
Q2: How do I identify the rail section I have?
A2: Measure the height, base width, and head width. Compare these measurements against a standard rail chart (ASCE, AREMA, UIC). Also, check the web of the rail for rolled markings that typically indicate the weight per yard (e.g., “136 RE”) and manufacturer.
Q3: Can I use a 115 lb clip on a 132 lb rail?
A3: Generally, no. The 132 lb rail has a wider and thicker base than the 115 lb rail. Using a clip designed for the smaller rail dimensions will likely result in improper fitment, overstressing the clip, or failure to secure the rail toe adequately.
Q4: What does “RE” stand for in rail specifications like 115 RE?
A4: “RE” stands for “Railroad Engineering,” indicating the profile was standardized by the American Railway Engineering Association (AREA/AREMA). These profiles were optimized from older sections to improve strength and ride quality for heavier trains.
Q5: What is the difference between Tee rail and Crane rail?
A5: Tee rails (used for trains) have a taller profile with a thinner web to flex slightly under load. Crane rails have a squat, thick profile with a very wide head and web to support immense vertical loads from crane wheels without bending or crushing.
