The rail system, especially freight rail transport is competing against modes having much lower noise and vibration emissions of the wheels. Also rehabilitation work often completely blocks tracks because of the absence of redundancies (tracks with low usage in parallel). Increasing axle weights and velocities create problems for single sleeper gravel based tracks. This results in frequent rehabilitation work which naturally blocks the train operation. With solid trackways there is a solution available which however has other disadvantages. The new system combines low pressures for the soil with low noise absorption and high stability.
The project aims at:
- reducing noise and vibration emissions
- reducing rehabilitation work by 70-80%
- reducing the cancellation time for tracks
- reducing the pressure impact on the soil
- improving the stability of the tracks
The main problems to be solved were the joining of two tracks and the reduction of the types of frame sleepers necessary to build a switchyard system. The new system shall also allow an employment of the existing maintenance and reconstruction machineries.
The project is devided into several phases. In the first phase the measurements will be undertaken to document the status quo. In the following phase, the stiffness parameters of the sleeper-gravel system will be optimised. The third step is a laboratory test. Here the new frame sleepers will undergo experimental testing. Last but not least the prototypes of the new frame sleepers shall be tested under normal operation accompanied with measurements of noise emission but mainly the stability - eventual changes in geometry.
The project has validated the hypothesis of decreased lifecycle costs. This ensures that using existing gravel based tracks keeping their benefits (like full mechanisation of the maintenance and reconstruction and existing supply structures) is possible. The erection and the maintenance may employ the adapted existing machines which is a major improvement compared to a change in the design philosophy requiring new equipment.
The pressure on the gravel was reduced by 50%, the stiffness is much higher and allows usage in inclined high speed rail arches. The tests were conducted at
A special improvement was found when connecting bridges. The new frame sleepers reduce the forces to the bridge support. It was also found out that the intermediate layer has the biggest impact on the noise emission. Further increase of the production quantities for the new systems will further enhance the return on investments.
Rail infrastructure operators are advised to think about changes in the sleeper technology. The new system combines the benefits of grave based systems with the benefits of concrete foundings (solid track surface).