DEMOSLEEPER

Project description

Sleeper, together with the rail, is the most important component of track superstructure in ballasted track.
Their quality conditions have considerable influence on the overall superstructure quality. Moreover, track maintenance costs are affected by this element due to their higher number. For many years now, prestressed concrete sleepers have replaced the use sleepers in other materials (wooden or metallic). All the shapes of normal types of sleepers can be substituted with prestressed concrete.

Previous UIC activities have set up the fundamental basis for the design of prestressed monoblock concrete sleepers, which have served afterwards to produce a series of European standards in cooperation with the manufacturing industry.

However, there are still complementary topics to be covered or expanded, in terms of:

• latest state of the art
• design,
• current and expected speeds and loading cases
• other track gauges (apart from the standard one, 1435mm) and the influence in terms of charges applied and efforts
• recommendation for use and maintenance practices of concrete sleepers
• the interaction with other superstructure components, such as:
  • the use of USP-Under Sleeper Pads,
  • ballast and the design of sleepers to avoid the flying ballast phenomenon under higher speeds.
    Additionally, these subjects should have a global application, even more extended than the EU space.

This project will contribute both to the “technical-economical asset management” and “improving the system utilization operating safety passenger and freight services and overcome infrastructure limitation to heavy and long trains” themes of the Rail System Forum Strategy, and fits with the maintenance optimization objective of the Rail Technical Strategy Europe. Likewise, it is complementary with the S2R Objectives to reach a safe, interoperable, reliable and cost-effective infrastructure.

Project objectives

The project aims at analysing factors of design and providing recommendations for the use of monobloc concrete sleepers, under of specific loads and maximum operative speeds.

Main tasks

• Benchmark of existing regulations and experience among infrastructure managers regarding design, inspection procedures, basis of experience and use of monoblock concrete sleepers (through questionnaires and interview, extended to all UIC members).
• Identification of combination of maximum speed and static load cases.
• Assessment of actual loading cases and their impact on safety, fatigue, maintenance, and durability needs.
• Identification of manufacturing, dosage techniques and production control.
• Numerical modelling of the behaviour of sleepers under dynamic and repeated static overloads.
• Recommendation and guidelines for a common approach and implementation of appropriate monoblock concrete sleepers design management.
• Recommendations for the use of concrete sleepers with USP-Under Sleeper Pads.

Project members

Administrator de Infraestructuras Ferroviarias

Infrabel S.A.

Société Nationale des Chemins de fer Français

RFI

UIC contact

For further information, please contact:

• Marcos Conceição

Deliverables