Anti-collision of trams and light rail vehicles

Abstract: In order to improve the anti-collision of trams and light rail vehicles, the anti-collision car body structure was developed and tested and verified.

Keywords: tram; light rail vehicle; collision resistance

1 Overview

In the summer of 2004, the Safetram project to improve the safety of light rail passengers and passengers in collisions is about to be completed. The Safetram project was launched on July 1, 2001 for a period of 3 years, funded by the European Union, and is part of the fifth framework research project.

To some extent, due to the Kyoto Protocol and related efforts to reduce carbon dioxide emissions and energy consumption, tram lines and light rail lines around the world are undergoing a renaissance stage. Factors contributing to the increase in tram and tram train (called suburban train) projects include greater transportation than buses, lower energy consumption, and lower cost and convenience than traditional heavy-duty subways.

The energy-saving advantages of light rail include light vehicle body structure and regenerative braking, but conversely, it is this light structure that will cause problems in terms of collision resistance. On unisolated lines, trams must share the road with other users and often drive without fixed signals. Both of these factors increase the risk of crashes.

The Safetram project is specifically designed to improve the cost-effectiveness of passive safety--that is, by ensuring a collision-resistant surviving space between vehicles, to reduce the impact force and extend the duration of the impact, thereby avoiding violent impact. The main objective is to demonstrate the feasibility of controlling the collision energy and acceleration of typical trams and tram trains at an acceptable cost within the limits of technology.

The project is based on the heavy rail collision prevention plan implemented by the railway operator, the rte EuramSafetran project, the automotive industry experience and the European Crossral project. The work is shared by 13 partners, who represent research institutions, manufacturers and operators, and are led and coordinated by the Portuguese company of the Ministry of Transport of Bombardier.

The Safetram project started with accident statistics and risk analysis, and reviewed the design and manufacture of the front end of the collision-resistant car body. For road accidents, the regulations on vehicle structure and internal passive safety are also studied, and the regulations on highway vehicles are reviewed, which will affect the performance of trams in the collision between these two types of vehicles and emphasize the applicability of the general safety concept .

In order to obtain the collision performance and optimized crushing characteristics under different collision situations, a two-dimensional multi-body dynamics model was used to simulate the overall dynamics of urban trams and suburban vehicles.

This modeling process, as well as the subsequent dynamic tests and verification of the results of the components and the entire vehicle body, will prepare for the development of standards for future vehicle design. To achieve this goal, the project is working with the European Standardization Committee 256 Technical Committee Working Group 2 to develop European standards for anti-collision structures.

The research results of the Safetram project will form the basis of Type IV and V trams in Part 2 of European Standard 12663 of the European Standardization Committee. This will greatly help to meet the passive safety requirements of tram operators, and we believe that it will eventually help eliminate the operational barriers of the market for rail public transportation vehicles.

2 Risk analysis

At present, the running safety of trams mostly depends on dynamic factors, such as high-performance braking. In order to meet the requirements of light vehicles, the body shell of urban trams can usually withstand 200kN ~ 400kN impact load without structural deformation, and the suburban car body shell can withstand 600kN impact load without structural deformation. The vehicle can withstand at least 1500kN impact load without structural deformation.

However, tram accidents have occurred frequently, causing injuries to passengers, passengers, pedestrians, car drivers and other road users. In the past 10 years, only 6 operators in Europe have reported 19,000 accidents, causing 3,050 casualties.

Two different raw data are used to assess the risk, and the product of the frequency of a given accident type and the severity of its consequences is defined as the risk of injury. For urban trams, the accident database of the existing road network is used. Since there is no comparable database for the tram train project, the statistics of regional train operation accidents by the German Federal Railway DB) and the French National Railway (NCF) are used.

An assessment of the tram accident in the country of the project partner and Belgium quickly revealed that the greatest danger to passengers and passengers came from the violent emergency braking, not from the actual relationship with the other car. hit. The analysis determined that a low-floor tram and a truck collided, resulting in an injury risk of 10-9 per passenger kilometer for passengers on the vehicle, and an injury risk of 10-7 for emergency braking.

In order to reduce the severity of injuries to passengers and passengers of trams, the project partners believe that it is very important to improve the passive safety of vehicles. The design of the anti-collision vehicle requires it to be crushed in a controlled and progressive manner, ensuring that the loss of surviving space in the driver and passenger areas is minimized. By controlling the collision energy and redesigning the internal structure of the tram, the safety of passengers and passengers can be improved. By ensuring progressive crushing and deformation, the deceleration can be controlled and limited to an acceptable level.

In the next phase of the project, 4 collision scenarios were set for each of the 2 main models:

C1: Emergency braking of urban tram (.73m / s);

C2: The same city tram collided at 20km / h;

C3: The city tram collided with a light box truck parked at a 45º angle to the track at a speed of 25km / h;

C4: The city tram collided with a suburban car at a speed of 10km / h;

P1: The suburban car collided with an 80t railway car equipped with side buffers at a speed of 25km / h;

P2: The suburban car collided with an anti-collision train weighing 129t at a speed of 22km / h;

P3: The same suburban car collided at 36km / h;

P4: The suburban car collided with a rigid truck weighing 16.5t at the level crossing at a speed of 40km / h.

In the P2 collision scenario, the anti-collision train refers to a train with modern force-displacement characteristics at the front end.

In order to obtain the crash performance under different scenarios and the crushing characteristics of target optimization, a two-dimensional multi-body dynamics model was used to simulate the overall dynamic performance of the vehicle.

3 Design and test

Based on the initial research, the afetran project team created two new design concepts for the city and suburban trams. In order to test different materials, it was decided to use aluminum to make urban tramcar bodies (Figure 1) and steel to make suburban car bodies (Figure 2).

Design of aluminum cab module for collision-proof city tram

Figure 1 The design of the aluminum cab module of the anti-collision urban tram

Design of steel cab for suburban car

Figure 2 The design of the steel cab for suburban cars

In order to simplify the application of the anti-collision principle, a lot of emphasis is placed on modularity. For example, the cab is designed as an integral module with a clear mechanical interface, and the deformation unit is designed as a separate module. The reliability of replaceable parts used to absorb energy in a crash will increase, and reduce the maintenance and life cycle costs of trams and light rail vehicles.

Guangzhou Ehang Electronic Co., Ltd. , https://www.ehangmobile.com

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