Steel Monoblock Sleeper Structure for Stable Rail Load Transfer

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Solution Overview

Problem

Existing railway sleepers, particularly steel trough sleepers, face issues with service life, stability, flexibility, track narrowing, corrosion resistance, and resonance behavior, and require complex installation due to protruding end caps.

Innovation Solution

A steel monoblock sleeper is created by filling a hollow profile with a molded body, preferably using polyurethane, to enhance load transfer and stability, and incorporating angle irons and ribbed plates for improved shear force distribution and rail fastening, with optional coatings for corrosion resistance and sound damping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If steel trough sleepers are used with hollow profiles, then manufacturing cost is reduced and weight is decreased, but service life and stability are compromised due to hollow layers

Engineering Contradiction:
Improvesleeper weightVSAvoidservice life
Core Design Contradiction:
Weight of stationary objectVSReliability

Solution Approach 1:

The patent applies composite materials by combining steel hollow profiles with concrete fill material. The steel provides structural framework and corrosion resistance, while the concrete fill eliminates hollow layers that cause instability. This composite construction achieves both weight reduction compared to solid concrete sleepers and improved service life through the protective steel outer shell.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The concrete shaped body is nested within the steel hollow profile. The steel trough body serves as a container that holds the concrete fill material, creating a nested structure where the inner concrete body is surrounded by the outer steel shell, eliminating hollow cavities while maintaining structural integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If hollow steel trough sleepers are used, then production cost is reduced, but load transfer behavior and stability deteriorate

Engineering Contradiction:
Improveproduction costVSAvoidload transfer behavior
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The composite structure combines steel and concrete materials to achieve superior load transfer behavior. The concrete fill material provides mass and stability for effective load transfer to the track bed, while the steel hollow profile provides structural integrity and corrosion resistance, together achieving better load transfer than hollow steel sleepers alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The concrete fill is strategically placed in specific sections of the steel hollow profile, particularly in areas requiring enhanced load transfer capability. This localized addition of mass and structural material improves load transfer behavior without requiring complete solidification of the entire sleeper.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If conventional steel trough sleepers are used, then flexibility in use is limited, but resistance to track narrowing in derailments is insufficient

Engineering Contradiction:
Improveflexibility in useVSAvoidtrack narrowing during derailments
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The composite steel-concrete structure provides enhanced resistance to track narrowing during derailments. The concrete fill material adds mass and structural rigidity, creating a more robust sleeper that better resists the forces generated during derailment events, while the steel outer shell maintains flexibility and adaptability in various track conditions.

Inventive Principle:
Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides enhanced durability, stability, reduced resonance, improved track gauge maintenance, and simplified installation by eliminating voids and optimizing force distribution, while minimizing corrosion and noise.

Implementation Method 1

at least one section of the steel sleeper trough body is filled to fill the profile with at least one molded body made of fully reacted reactive material

Methodology Applied
Scientific EffectPolymerization reaction: Photopolymerisation

Implementation Method 2

This creates a larger contact surface in order to be able to transfer transverse forces that occur transversely to a rail direction to a track bed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4245917B1Monoblock steel tie and method for its production
Publication Date: 2026.04.29 BAUPOLY AG
  • EP4245917B1 patent drawingFigure 1~3
  • EP4245917B1 patent drawingFigure 4~5
  • EP4245917B1 patent drawingFigure 6~7a

AI summary

The invention relates to a steel monoblock sleeper (1) comprising a steel sleeper trough body (100) made of a hollow profile (130) with end caps (160) bent at opposite ends (150) of the steel sleeper trough body (100), wherein the steel sleeper trough body (100) is filled to fill the profile at least in sections (190) which are provided for rail fastening by means of at least one shaped body (400).A preferred method for manufacturing a steel monoblock sleeper (1) comprises the process steps of: (a) providing or manufacturing a steel sleeper trough body (100) from a hollow profile (130) with bent end caps (160) at the opposite ends (150); and (b) arranging or forming at least one shaped body (400) in at least one section (180, 190) of the steel sleeper trough body (100), and connecting it to the steel sleeper trough body (100) such that the at least one section (180, 190) of the steel sleeper trough body (100) is filled by the at least one shaped body (400) to fill the profile.