TURNOUTS - New Concepts for Turnouts in Urban Rail Transit Infrastructures
Overview
Background & policy context:
There is a significant difference between railway operations and urban transport (tram, metro) operations. The main one is speed. The speed varies from 100 km/h for a freight train to 160 km/h for medium-distance trains to 350 km/h for high-speed trains. In comparison, the maximum speeds of a tram and metro are far lower at respectively 50 and 100 km/h. Railway axle loads range from 18 tonnes for passenger coaches to 22.5 tonnes for freight and locomotives, whereas axle loads for tram and metro range from 8 to 14 tonnes.
Railways usually face fewer geographical and thus environmental concerns, as they run separately, typically at a greater distance from houses. Metros and trams face significant space constraints as they operate in an urban environment. Metro tracks are in a tunnel and turnouts cause great concerns, especially in terms of noise and vibration. Trams operating on the streets, often close to houses, cause similar problems.
In addition, trams operating on the street require special (girder) rails and thus special turnouts.
All these elements show that, even though the basic concepts are the same, turnouts developed for railways cannot be simply implemented in urban transport.
Objectives:
The objective of the project is to improve the vehicle-track interaction of turnout systems as used in urban rail transit, and therefore improve their efficiency, enhance their safety levels, reduce their maintenance costs, increase their life expectancy and restrain the emitted noise.
Methodology:
The TURNOUTS project starts with the modelling of actual turnouts to provide the benchmarks against which the improvements will be measured. Design changes will be implemented in the models to predict their behaviour. The turnouts will be manufactured and installed for validation purposes and measurements will be performed to confirm the predictions from the models. The end result will be a series of turnouts with improved characteristics.
The project is divided into several groups of activities:
- Six different existing turnout systems representing the conventional turnouts used today will be measured and modelled. The models will be optimised to reflect the actual measurement results. Improvements and changes will be made to these turnouts. The models will then be used to optimise the proposed changes.
- A large number of potential measures to reduce impact forces will be defined. Conceptual design studies will be made for some of these designs.
- Seven test sites will be selected within the networks of the participating operators and the most optimal design for each particular location will be developed.
- The most optimal designs will include the use of new materials, new manufacturing techniques and new installation techniques. The selected designs will be manufactured and tested in the lab.
- After installation, the performance of the designs will be tested and compared against the calculated results.
- The results of the new designs will be used to develop conclusions about the benefits of various designs.
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