115 lb RA Railroad Tie Plate

115 lb RA tie plates are a specific vintage of North American track hardware. While "RA" (American Railway Association) standards have largely been superseded by modern AREMA (RE) standards, these plates remain critical for maintenance and historical restoration. 

Technical Context: RA vs. RE

• Historical Standard: The RA designation refers to older profiles developed by the American Railway Association. While the nominal weight (115 lbs/yd) is the same as the modern 115 RE, the cross-sectional shape and base width can vary slightly.

• The "RA" Profile: The "RA" profile was part of a movement to optimize rail for heavy freight. Because the rail's shape is different, specialized RA tie plates are required to ensure the rail base is seated securely between the shoulders. 

Typical Specifications

Functional Design

• The 1:40 Cant: These plates are beveled to provide a 1:40 inward slope. This rotation centers the train's weight over the rail web, which reduces wear on the rail head and improves lateral stability during high-speed or heavy freight operations.

• Double Shoulder: As seen in your image, modern versions are almost always "double shoulder," meaning they have two raised ridges that physically lock the rail base in place, preventing it from sliding sideways. 

A standard technical drawing for a 115 lb (RE or RA) double-shoulder tie plate specifies the dimensions and punch patterns required for compatibility with a 5-1/2" rail base.

Standard Engineering Dimensions

For a 14-inch double-shoulder plate used on 115 lb rail, the following measurements are typical:

Key Drawing Features

• Field vs. Gauge End: The plate is asymmetrical; the "long end" (field end) is installed on the outside of the track, while the "short end" (gauge end) sits inside.

• Punching Patterns: Drawings specify "Line Holes" (immediately next to the rail base) and "Hold-Down Holes" (closer to the plate edges).

• Inclined Ends: The ends of the plate are often beveled or inclined to prevent "digging" into the wood tie under load.

Signum specializes in AREMA tie plates, specifically for 115RE or 136RE rail sections. We currently support North American infrastructure projects by providing forged,rolled and cast plates that meet Plan 8 and Plan 12 specifications.We’d love to send over our latest technical data sheets and lead times for your maintenance cycle if you need.