Term: Railroad tie
**Types of Railroad Ties:**
– Stone block ties were used on early railways like the Liverpool and Manchester Railway.
– Stone blocks were later replaced by timber ties due to maintenance issues.
– Bi-block ties with tie rods have similarities to stone block ties.
– Historical wooden ties were made by hewing or sawing softwood and hardwood timbers.
– Softwood ties are treated with preservatives like creosote or copper azole.
**Materials Used for Railroad Ties:**
– Stone Block Ties:
– Stone block ties were used on early railways.
– Stone blocks were replaced by timber ties due to maintenance issues.
– Bi-block ties with tie rods are similar to stone block ties.
– Stone block ties allowed horses to tread the middle path safely.
– Stone block ties were not suitable for soft ground.
– Wooden Ties:
– Historical wooden ties were made from softwood and hardwood timbers.
– Softwood ties are treated with preservatives like creosote.
– Wooden ties are susceptible to rot, splitting, and insect infestation.
– Some timbers like sal or jarrah are durable enough to be used untreated.
– Wooden ties can catch fire and develop cracks with age.
– Concrete Ties:
– Concrete ties are cheaper and easier to obtain than timber ties.
– Concrete ties have a longer service life and require less maintenance.
– Concrete ties are quieter than wooden ties on straight stretches.
– Concrete ties are required on high-speed lines in the UK.
– Most European railways use concrete bearers in switches due to cost and durability.
– Steel Ties:
– Steel ties are trough-shaped and lighter than concrete ties.
– Steel ties can be installed on existing ballast beds.
– Steel ties are 100% recyclable and require less ballast than wood or concrete.
– Modern steel ties handle heavy loads and adverse track conditions.
– Steel ties are economical to install and widely used in various railroad sectors.
– Plastics:
– Composite railroad ties made from recycled plastic resins and rubber claim a service life of 30-80 years.
– Plastic ties are resistant to rot, insects, and can offer additional lateral stability.
– Environmental benefits include replacing toxic creosote-treated timber ties.
– Hybrid plastic ties are used in various rail applications and offer benefits on bridges.
– Network Rail began replacing wooden ties with recycled plastic in 2009.
**Design and Applications of Railroad Ties:**
– Non-conventional Tie Forms:
– Y-shaped ties reduce ballast volume due to load-spreading characteristics.
– Y steel ties have high noise levels but excellent resistance to track movement.
– Twin ties like the ZSX Twin tie are suitable for tracks with sharp curves and bridges.
– Wide ties increase lateral resistance and reduce ballast pressure.
– Bi-block ties offer increased lateral resistance and are used on high-speed TGV lines.
– Dimensions and Spacing:
– Mainline railroad crosstie spacing is around 19-19.5 inches for wood ties and 24 inches for concrete ties.
– In the UK, sleepers are typically 8ft 6in long, 10 inches wide, and spaced 2ft 7in apart.
– Historical UK sleeper spacing varied based on rail length and joint proximity.
– The spacing at rail joints allowed for thermal expansion gaps.
– Different methods exist for fastening rails to railroad ties.
– Fastening Rails to Railroad Ties:
– Historical methods include spikes and cast iron chairs fixed to ties.
– Modern methods like Pandrol clips use springs to fix the rail to the tie chair.
**Reuse and Disposal of Railroad Ties:**
– Other Uses:
– Wooden ties can be recycled into sculptures or repurposed for various artistic or functional projects.
– Stone blocks from old railways can find new life in construction projects like loading docks.
– Railroad Ties in Gardening and Landscaping:
– Popular for creating retaining walls and raised-bed gardens.
– Used for building steps.
– Often made from decommissioned rail ties.
– Lifespan limited due to rot.
– New oak or pine beams available in the UK for garden construction.
– Railroad Ties in Construction:
– Used near railroad tracks, particularly by railroad employees.
– Entrepreneurs sell new ties for construction purposes.
– Introduce soil pollution due to dangerous chemicals.
– Some properties avoid them due to pollution concerns.
– Used in the UK for garden construction with non-toxic beams.
**Regulations and Innovations Related to Railroad Ties:**
– Railroad Ties in Law and Regulations:
– Germany prohibits their use as building material since 1991.
– Regulated by specific by-laws to protect health and the environment.
– Restrictions on areas frequented by children and in food production.
– Health risks associated with wooden railroad ties.
– Concerns about pollution from wood preservatives.
– Railroad Ties in Industry and Innovation:
– Steel sleepers still made and have a historical significance.
– Various publications and studies on railway engineering.
– Testing of polymer rail ties for the mining industry.
– Transition to recycled plastic sleepers by Network Rail.
– Development of composite railroad ties for various applications.
A railroad tie, crosstie (American English), railway tie (Canadian English) or railway sleeper (Australian and British English) is a rectangular support for the rails in railroad tracks. Usually laid perpendicular to the rails, ties transfer loads to the track ballast and subgrade, hold the rails upright and keep them spaced to the correct gauge.
Railroad ties are traditionally made of wood, but prestressed concrete is now also widely used, especially in Europe and Asia. Steel ties are common on secondary lines in the UK; plastic composite ties are also employed, although far less than wood or concrete. As of January 2008, the approximate market share in North America for traditional and wood ties was 91.5%, the remainder being concrete, steel, azobé (red ironwood) and plastic composite.
Tie spacing may depend on the type of tie, traffic loads and other requirements, for example 2,640 concrete ties per mile on North American mainline railroads to 2,112 timber ties per mile on LMS jointed track.
Rails in the US may be fastened to the tie by a railroad spike; iron/steel baseplates screwed to the tie and secured to the rail by a proprietary fastening system such as a Vossloh or Pandrol which are commonly used in Europe.