Internal Bogie Frames in Articulated Rail Vehicles for Longer Cars

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Solution Overview

Problem

Existing rail vehicles with articulated train designs face challenges in minimizing the number of components and reducing acquisition, energy, and maintenance costs while maintaining passenger transport capacity and vehicle length.

Innovation Solution

The design incorporates internally mounted bogie frames with wheels positioned further outwards than the longitudinal members, extended overhangs on end car bodies to accommodate heavy components, and optimizes bogie configurations to reduce weight and axle loads, allowing for fewer car bodies and bogies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the number of bogies is reduced to minimize components, then acquisition and maintenance costs are reduced, but the vehicle length and passenger capacity are limited

Engineering Contradiction:
Improvenumber of bogiesVSAvoidvehicle length
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The bogie frame is nested within the car body structure, with the bogie frame positioned inside the car body's longitudinal space. This integration allows the bogie to contribute to both wheel support and structural integrity, effectively utilizing space and reducing the need for additional external structural components that would increase vehicle length.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The invention transitions from conventional external bogie mounting to internal bogie frame integration, changing the spatial arrangement from three-dimensional external placement to two-dimensional internal positioning. This dimensional reorganization allows compact packaging of the bogie within the car body envelope, enabling longer vehicle lengths without proportionally increasing bogie count.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If car bodies are made significantly longer to reduce the number of car bodies, then fewer components are required, but the axle load on individual bogies increases

Engineering Contradiction:
Improvenumber of car bodiesVSAvoidaxle load
Core Design Contradiction:
Device complexityVSForce

Solution Approach 1:

The bogie frame is designed with non-uniform cross-sectional properties along its length, with varying heights and thicknesses optimized for local stress conditions. The frame height and material distribution are adjusted to provide maximum strength where axle loads are highest (near the bogie-wheel interface) while reducing material where loads are lower, enabling the structure to support longer car bodies without exceeding axle load limits.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bogie frame utilizes composite construction combining different materials with complementary properties - high-strength steel for load-bearing critical sections and lighter materials for non-critical portions. This composite approach allows the frame to withstand increased axle loads from longer car bodies while maintaining overall weight efficiency.

Inventive Principle:
Principle #40Composite materials

3Weight of moving object

If internally mounted bogie frames are used to reduce weight, then permissible axle loads are better managed, but the overall vehicle weight distribution changes

Engineering Contradiction:
Improvevehicle weightVSAvoidaxle load distribution
Core Design Contradiction:
Weight of moving objectVSForce

Solution Approach 1:

The vehicle design incorporates adjustable weight distribution mechanisms that allow the center of gravity to be dynamically positioned along the vehicle length. This enables optimization of axle load distribution to match the reduced weight from internally mounted bogies, ensuring that weight is properly balanced between axles while maintaining the weight savings benefit.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3164313B2Articulated train-type rail vehicle
Publication Date: 2025.10.15 SIEMENS MOBILITY GMBH
  • EP3164313B2 patent drawingFigure 1~4

AI summary

The invention relates to a rail vehicle for transporting people, designed as a motorized articulated train and comprising at least two car bodies (1, 2); adjoining car bodies (1, 2) are supported on a common central running gear (4, 9), and terminal car bodies (1) are additionally supported on terminal running gears (3, 8); for all of the running gears (3, 4, 8, 9), the distance between the centers of the bogies of two adjoining running gears (3, 4, 8, 9) is 18 to 21 m, and the terminal car bodies (1) have a length of 24 to 27 m.