RSSB 2413 - Loading requirements for Track Systems - Work package 2 - Development of a methodology to determine loading regimes for track designers - Extension of Deadline to Friday 11th August

The design of track systems is continually developing, using combinations of different materials, improved manufacturing processes and construction techniques. Track systems are increasingly required to carry a wider range of traffic and vehicle types and therefore need to be tailored to suit a range of variables. Whilst experience and evolution of design practice has taught track designers which combinations of components can work there is not an agreed set of loading requirements that can be used to help clients and designers install a demonstrably optimum arrangement of track parameters that can deliver the required performance of the track system over its design life. To support the GB rail industry, the first phase of an in-depth study of the track loading requirements to determine an appropriate set of parameters for design of track systems has been undertaken. This included a literature review covering the origins and application of track and bridge loading, loading practice adopted for other transport assets (e.g; highway pavements), and compilation of project and customer experience, with input from experts in vehicle and structural dynamic load modelling, and bridge and track design. [The first report is available on SPARK (https://www.sparkrail.org), RSSB's rail knowledge hub. The report can be accessed by searching for "T1073" on SPARK or visiting the page https://www.sparkrail.org/Lists/Records/DispForm.aspx?ID=24275. In order to download the report, you will need to register for SPARK. This is free of charge and available to all.] The aim of this work pa

The objectives apply to the track support system from the top of the rail to the subgrade.

The objectives of the work package are:

1. To develop a methodology for determination of appropriate load models for the design of track systems. The methodology should take in to account the associated key variables identified in Phase 1, including, axle weight, speed, track geometry (specifically curvature and associated cant effects) and variation in wheel and track condition and trackbed resistance.

2. To determine the maximum vertical, horizontal and longitudinal loads likely to be encountered for the rolling stock parameters considered and which should be applied for the design of particular track systems.

3. To determine the primary structural characteristics of track systems and their potential influence on the magnitude of the forces that are applied or the load effects that should be considered (e.g; influence length, resonance etc) to the track in the design process.

4. To determine for the primary load cases, the appropriate combinations of vertical, lateral and longitudinal loads due to railway traffic, and the influence of the associated environmental load due to wind (quasi-static load).

5. To develop guidance on the application of the methodology referred to in 1, taking account of objectives 2, 3, and 4.

6. To provide an independent verification of the models.