Prefabricated Sleeper Units for Rapid Ballasted Track Conversion

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Solution Overview

Problem

Existing methods for converting ballasted tracks to slab tracks are not suitable for short stretches of track and require lengthy interruptions in traffic, as they involve significant changes to the track structure and cannot be completed in a manner that allows for immediate reuse.

Innovation Solution

A method that allows for the conversion of ballasted tracks to slab tracks by removing ballast in sections, allowing for the installation of adjustable supports and prefabricated sleeper units without altering the rail position, enabling partial track usage during construction and minimizing downtime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the existing bedding is expanded and the track is placed on the substructure, then a solid slab track can be produced, but the conversion requires lengthy interruptions in traffic and is not suitable for short stretches of track

Engineering Contradiction:
Improvetrack stabilityVSAvoidtraffic interruption time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The track is divided into individual sleeper units that can be independently replaced. Each sleeper unit consists of a concrete slab with integrated rail fastenings, allowing section-by-section conversion without shutting down the entire track. This segmentation enables maintenance work on short stretches while keeping the rest of the track operational.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sleeper units are pre-assembled with rail fastenings and concrete slabs before being installed on the track. This preliminary preparation allows for rapid installation - the units are simply placed into position and secured, eliminating the need for on-site concrete pouring and extended curing times that would cause traffic interruptions.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the track is dismantled and rebuilt to produce a slab track, then a solid track structure is achieved, but the position of the rails must be changed and extensive reconstruction is required

Engineering Contradiction:
Improvetrack structureVSAvoidreconstruction complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The concrete sleeper units serve multiple functions: they provide the solid slab track structure, incorporate the rail fastenings, and maintain the existing rail positions. This multi-functionality eliminates the need for separate components and simplifies the conversion process by combining track structure and fastening systems into a single integrated unit.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of removing rails and reconstructing the track structure first, then repositioning rails, the invention inverts the approach by keeping rails in their original positions and installing sleeper units with integrated fastenings around them. This reversal of the conventional construction sequence dramatically reduces reconstruction complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If ballast is removed in a section extending over several sleepers to create space for slab track construction, then a solid track can be built, but additional adjustment devices are needed for vertical adjustment of the rails

Engineering Contradiction:
Improvetrack structureVSAvoidadjustment device complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The adjustment mechanism is merged directly into the sleeper unit itself through integrated adjustment spindles. These spindles are built into the concrete slab and provide vertical adjustment capability without requiring separate external adjustment devices. This integration eliminates additional complexity while maintaining the ability to adjust rail positions vertically.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2740842B1Method for converting a gravel track into a solid track
Publication Date: 2017.09.27 SONNEVILLE
  • EP2740842B1 patent drawingFigure 1~2
  • EP2740842B1 patent drawingFigure 3~4
  • EP2740842B1 patent drawingFigure 5~6

AI summary

The method involves removing ballast in a section (6) that is extended over several sleepers. Sleeper blocks (10) are inserted vertically and fastened to rails (5). An infill concrete (24) is filled in from the underground to height of the sleeper blocks after the infill concrete is hardened. Vertically adjustable support units are inserted on which the rails are resting and are supported on the underground. Support portions located between two respective sleeper blocks in the direction of the rails are removed. Independent claims are included for the following: (1) sleeper unit; and (2) support unit.