THE North American freight railway industry is continuing to embrace new technologies that are helping to improve safety, efficiency, productivity, and customer service. A wide range of organisations are advancing rail technology on several fronts including the railways, the Association of American Railroads' (AAR) strategic research initiatives programme, suppliers, government entities, shippers, wagon owners, and universities.
There is a clear trend towards detector and performance-based rolling stock maintenance to improve efficiency by reducing the cost of maintenance and inspection. Wayside detectors identify defects on passing wagons, including overheated bearings and damaged wheels, dragging hoses, deteriorating bearings, cracked wheels, and imbalanced loads. The number and types of detectors with internet data access capability has grown rapidly in North America as new technologies come online. Trackside detectors are able to send actionable information regarding the health of equipment owned by both the railways and private wagon owners over the internet.
Fully-automated wagon inspection and scanning systems, based on machine-vision technologies, and wheel profile and brake shoe inspection systems, are being developed and introduced into revenue service which will further reduce derailments and improve the safety of wagon inspectors over the next decade.
The Asset Health Strategic Initiative (AHSI) under development by AAR's wholly-owned IT subsidiary, Railinc, is seeking to reduce mechanical service interruptions, improve the quality of wagon inspections, and increase rail yard and repair shop efficiency. AHSI will consider the entire rolling stock health cycle, including prevention, detection, planning, movement, repair, and settlement.
Continuing advances in rolling stock component design and materials for heavy axleloads and high-mileage wagons are essential for improving service reliability and safety. Accelerated research to improve wheel and axle designs and materials, couplers and knuckles, and improved bogies are underway to significantly increase the service life of these components while reducing scheduled maintenance and repair requirements.
Advanced materials and non-destructive testing (NDT) methods for wheels are of particular interest in prolonging the life of this critical component. Current research is focused on the testing and evaluation of higher-strength wheel steels in revenue service as well as the development of cost-effective cracked wheel detection systems. Root cause analysis of wheel failures due to vertical split rims is continuing to develop prevention and detection methods to eliminate wheel-caused derailments.
There is continuing progress in wheel/rail interface design and management methods, with development underway of advanced simulation models describing the behaviour of wheel and rail materials under rolling contact as well as controlled tests. TTCI has recently installed a full-scale rolling contact fatigue simulator, built by MTS, at its test centre in Colorado, and has begun testing various wheel materials under a variety of operating conditions. Testing will continue into the next decade to develop strategies to prevent wheel/rail rolling contact fatigue (RCF).
In recent years, many US Class 1 railways have explored natural gas as an alternative locomotive fuel. Development of equipment to use gaseous natural gas as fuel is receiving a significant amount of effort, and may continue to do so long-term.
Recent advances in track inspection and maintenance procedures as well as improved track component designs and materials have substantially reduced track-caused derailments during the last decade.
Advanced inspection procedures, such as the phased-array rail inspection system, locomotive-mounted track integrity measurement systems, and mobile systems to measure rail neutral temperature are being developed to improve the safety of rail operations.
Research and field trials are underway for the inspection of track and bridges and inspection for track integrity ahead of key trains in dark territory.
Other inspection technology developments either underway or planned in the near future include:
- a high-speed platform to measure the coefficient of friction
- a high-speed platform to measure RCF
- use of locomotives to inspect internal rail defects
- health monitoring of switches and switch machines
- machine vision track inspection
- high-speed machine inspection of wood and concrete sleepers, and
- ground penetrating radar (GPR) to inspect track substructure.
New and improved track component and bridge designs and materials are being evaluated initially at TTCI's Facility for Accelerated Service Testing (Fast) and then in revenue service. These components include fatigue-resistant rail, new-technology concrete sleeper designs, longer lasting timber or composite sleeper/fastener systems, alternative bridge designs and materials, and cost-effective special trackwork designs and materials.
To minimise the effect of heavier axleloads on lines where freight tonnage is increasing, research is underway to optimise gauge-face and top-of-rail lubrication using reliable delivery systems and cost-effective lubricants along with the application of science-based rail profile grinding and revolutionary rail joining methods.
Increasing the length and tonnage of trains provides the opportunity for increased system throughput with minimal impact on the cost structure. Initiatives by North American railways to meet customer expectations have made it possible to run longer train with higher axleloads.
The North American rail industry has already spent billions of dollars to develop, test and evaluate Positive Train Control (PTC) to meet the recently-extended deadline of 2018. However, a number of key developments, including improved data radio systems and cost-effective braking algorithms, need to be completed before widespread implementation can be achieved without significant negative operational impacts. Key developments, such as broken rail detection systems independent of fixed-block track circuits, perhaps through fibre optic systems, and improved train positioning and integrity monitoring systems, could eventually make more sustainable train control architectures viable for wide-scale deployment.
Looking towards the next 20 years, promising technology developments will continue to improve safety, efficiency, and service quality while responding to growing pressure to increase capacity, improve productivity, meet environmental challenges, boost fuel efficiency, and enhance security.