A theory is presented for retrieving the track/bridge frequencies and track modulus from an instrumented vehicle moving over a dual-beam model to simulate track-bridge system. The dual beams are connected by uniform spring-dashpot units effects of sleepers ballast, etc. Based on model, response firstly derived in closed form, along with that vehicle-track contact point. solved relate bridge fre...

Ballast rheology is a phenomenon that describes movements of ballast particles due to the discrete nature, which eventually leads bed fluid deformation after long-time service. In most cases, main reason track irregularity some defects, e.g., hanging sleeper and mud spots. Therefore, it significant confirm mechanism, not only benefits for alleviating prolonging service providing safe transporta...

The railroad industry was substantially deregulated by the Staggers Act in 1980. While railroad rates, as measured by industry-wide revenue per ton-mile, declined since that time, it is unclear why rates declined. Changes in commodity mix, length of haul, shipment size, lading weight, equipment ownership, railroad costs, competition from other modes, and demand for railroad transportation have ...

This paper proposes an ant colony optimization algorithm to assist railroad yard operational planning staff in their daily tasks. The proposed algorithm tries to minimize a multi-objective function that considers both fixed and variable transportation costs involved in moving railroad cars within the railroad yard area. This is accomplished by searching the best switch engine schedule for a giv...

T HROUGH an amendment to the Railroad Unemployment Insurance Act, approved by President Truman on July 31,1946, the Railroad Retirement Board was charged with the responsibility of establishing and administering a sickness insurance program for railroad employees.’ Thus, sickness benefits now form an integral part of the railroad retirement and unemployment insurance systems. The programs for p...

We measured the presence, viability and potential toxicity of cyanobacteria in ships’ ballast tanks during three domestic voyages through the North American Great Lakes. Using molecular methods, the toxin-producing forms of Microcystis and Anabaena were monitored in ballast water after ships’ ballast tanks were filled at their first port of call, and at subsequent ports as ships transited the G...

Biological invasions have the potential to cause extensive ecological and economic damage. Maritime trade facilitates biological invasions by transferring species in ballast water, and on ships' hulls. With volumes of maritime trade increasing globally, efforts to prevent these biological invasions are of significant importance. Both the International Maritime Organization and the Australian go...

Collapsible soils could widely be found in central part of Iran and has caused lots of problems for roads and railroads in that region. Appearance of wide cracks in the collapsible soil near the Tehran-Semnan railroad tracks has caused some worries regarding the safety and performance of the railroad. However, due to the high traffic of the railroad, it is impossible to block the road for remed...