The MODBRAKE project sought to make a significant contribution to the achievement of the ERRAC Strategic Rail Research Agenda (SRRA) published in 2002.
In the framework of the two railway packages, the High Speed and Conventional Rail Directives were being implemented through the publication of technical specifications for interoperability and validated via new and improved voluntary standards. The practical implementation of interoperability requirements however required a joint approach by the railway stakeholders to ensure that the standardisation process across Europe will become more efficient. Brake-related issues of interoperability and standardisation were thoroughly addressed within the MODBRAKE project.
The difficulty in developing and describing universal brake requirement specifications is a major handicap to the opening up of the Interoperable European Rail Network - a key element of EU single market policy.
The braking system is one of the most critical and complex sub-systems of rail vehicles, particularly as far as safety requirements at train-level are concerned. The brake system may be 5% of the value of the train but of far greater importance and complexity than most other items of similar value. In fact, up to 40% of the efforts in generating interoperability specifications for rolling stock and control command and signalling systems are related to braking performance and how it could best be achieved.
During the implementation of the MODTRAIN project, it became clear that this Integrated Project could not address brake-related issues beyond the brake-relevant interfaces in a sufficiently appropriate manner, and that there was a strong case for a separate project dedicated to braking performance, brake modules and their interfaces to TCMS and the other sub-systems of rolling stock. As a consequence, it is critical to carry out research on braking performance and brake module interfaces, which will enable a comprehensive approach to be applied to modular high-speed trains and universal locomotives. To reduce this complexity, and therefore the costs of brake systems, the project MODBRAKE proposes to develop a modular brake system.
The objective of the project was to develop a modular brake system in order to reduce the complexity, and therefore the costs of brake systems.
The related system specifications are determined, evaluated and tested to develop a modular brake concept. The standardised modules are interchangeable in terms of functions and interfaces, but they may still be specific to each manufacturer so as to guarantee future technological progress.
The MODBRAKE project focused on the braking system starting from the interfaces defined in MODTRAIN. The field of application for MODBRAKE is the same as for MODTRAIN: TSI high-speed trains and universal locomotives capable of speeds greater than 190 km/h.
A four-phase approach was adopted to achieve MODBRAKE's scientific and technical objectives.
In the first phase, the work concentrated on understanding the existing standards and regulations for brake systems on the one hand, and the interface results and the functional, system and safety requirements coming from the MODTRAIN project on the other hand.
In the second phase, the project focused on:
- a detailed determination and definition of standards for the functional requirement specifications and system requirement specifications for the identified modules (top down approach - harmonisation on system-level);
- (starting from existing specifications) an elaboration of complete standard proposals for a range of interchangeable components.
In the third phase, the modules, derived from the harmonised rolling stock architecture on the relevant level, were evaluated through life-cycle cost analysis. For this analysis, a software tool, already developed in MODTRAIN, was enhanced so as to be suitable for brake specific data on life-cycle costs.
As a result of this evaluation, two of the identified brake system modules are developed, tested and evaluated in the fourth phase of the project. An appropriate amount of interchangeable modules are identified, selected and specified within the macro-modules.
The main result of the project is the definition of specifications for the main modules of a modular brake system and its interfaces. The specification results in terms of design principles and interface definitions were successfully demonstrated and validated by functional prototypes for brake control and bogie equipment.
These specifications relate to the following areas:
1) Air Generation and Treatment
The specifications are concerned with air consumption calculation, the air supply module classes 1 600 and 2 400, and air quality. In general a description of the main technical parameters of a standard Air Generation and Treatment Unit for High Speed Trains with regard to functional requirements, mechanical, electrical and pneumatic interfaces for different air supply units has been provided. In addition, a reference procedure for the calculation of air consumption on a train, a specification for the air quality on board rolling stock and validation procedures of Air Generation and Treatment Units has been produced.
2) Brake Control
In general, the definition of three Brake Control architectures for Multiple Units with the aim to standardise the interfaces among the identified sub-modules has been provided. The following main architectures (all compliant to the Technical Specification for Interoperability High Speed requirements) have been taken into account:
- Indirect brake system based on UIC requirements;
- Direct/indirect brake system UIC compatible;
- Direct/indirect brake system.
In addition, Modbrake focused on the standardisation of the two following driver’s desk devices for functional requirements and mechanical, electrical and pneumatic interfaces:
- Drivers Brake handle/controller (position and time dependant);
- Emergency Brake push button.
3) The 'bogie brake module' generates the retarding force
Modbrake specified the requirements and interfaces as well as the operational environment of modern compact actuators/calipers that act on axle or wheels installed brake discs.
4) The interoperability issues for Eddy Current Brakes (ECB)
have also been addressed. ECB's are used for emergency brake or service brake applications to shorten the braking distance and relieve the wear and high thermal stress on the mechanical parts of the friction brake. The developed specification provides a working base addressing interope
A descriptive calculation has been performed using suitable tools for the Italian high speed train ETR 500. Promising results towards the modularisation of the braking systems have been obtained, supporting, upon an economic perspective, the final MODBRAKE purposes.
The defined specifications for the modular brake system have been proposed for European standardisation. The main implications if adopted relates to higher level of standardisation and interoperability of train brake systems.