19,631 research outputs found
Management of interstate rail rollingstock
The Study Group was asked to develop a methodology to allow more efficient and effective direction of empty wagon movements. The Study Group chose to develop two linear programming approaches. One was for allocating empty wagons, and the other modelled both empty and full wagons. Although large in size, the models were otherwise feasible, showing that, conceptually, the method would work. However, there is still a major amount of development work required to implement the system
Internal report cluster 1: Urban freight innovations and solutions for sustainable deliveries (1/4)
Technical report about sustainable urban freight solutions, part 1 of
LOGISTICS AND SUPPLY CHAIN STRATEGIES IN GRAIN EXPORTING
During the past decade, the grain shipping industry has become highly competitive and technologically advanced. These changes, along with the introduction of innovative shipping mechanisms, have made logistics management an important source of opportunity and risk for grain shippers. In this study, a stochastic simulation model was developed to evaluate the tradeoffs and effects of key variables on logistical performance in managing the grain supply chain. Average demurrage cost for the supply chain was $2.03 million with the greatest cost being for railcars and the least cost being for barges. Of the stochastic variables modeled, changes in export demand had the greatest impact on demurrage costs.Supply Chain, Grain Shipping, Logistics, Demurrage, Guaranteed Freight, Industrial Organization,
Transportation vehicle energy intensities. A joint DOT/NASA reference paper
A compilation of data on the energy consumption of air and ground vehicles is presented. The ratio BTU/ASM, British Thermal Units/Available Seat Mile, is used to express vehicle energy intensiveness, and related to the energy consumed directly in producing seat-mile or ton-mile productivity. Data is presented on passenger and freight vehicles which are in current use or which are about to enter service, and advanced vehicles which may be operational in the 1980's and beyond. For the advanced vehicles, an estimate is given of the date of initial operational service, and the performance characteristics. Other key considerations in interpreting energy intensiveness for a given mode are discussed, such as: load factors, operations, overhead energy consumption, and energy investments in new structure and equipment
E-business impacts for urban freight: results from an Australian study
E-Business is expected to dramatically change the way business is conducted internationally, nationally, within states and at the local area level. Moreover, these changes are very likely to happen well within the planning time frames required for provision of transport infrastructure and services. E-business is defined as including e-commerce, either between Businesses to Business (B2B) or Business to Customers (B2C), and the adoption of electronic technology within businesses. This paper presents some results from a study commissioned by the Australian National Transport Secretariat (NTS) to assist Australian business and government pro-actively address the transport issues arising from e-business. The resulting working papers will be used to establish a research framework for identifying policy and planning levers to maximize benefits to Australia from national and global e-business activity. The study sought to investigate three principal questions on e-business impacts: how will the transport task change; what will be affected; and how can the transport system respond? Current literature suggests that growth in e-business stems from the combined existence of market demand, suitable enabling technology, and skills and familiarity in management/users/ industry/government. The results of the study suggest that e-business will have implications for urban freight including higher levels of demand for goods and services, increased requirements for logistics distribution, changes in location preferences and improved transport network performance
Hump Yard Track Allocation with Temporary Car Storage
In rail freight operation, freight cars need to be separated and reformed into new trains at
hump yards. The classification procedure is complex and hump yards constitute bottlenecks
in the rail freight network, often causing outbound trains to be delayed. One of the problems
is that planning for the allocation of tracks at hump yards is difficult, given that the planner
has limited resources (tracks, shunting engines, etc.) and needs to foresee the future capacity
requirements when planning for the current inbound trains. In this paper, we consider
the problem of allocating classification tracks in a rail freight hump yard for arriving and
departing trains with predetermined arrival and departure times. The core problem can be
formulated as a special list coloring problem. We focus on an extension where individual
cars can temporarily be stored on a special subset of the tracks. An extension where individual
cars can temporarily be stored on a special subset of the tracks is also considered. We
model the problem using mixed integer programming, and also propose several heuristics
that can quickly give feasible track allocations. As a case study, we consider a real-world
problem instance from the Hallsberg Rangerbangård hump yard in Sweden. Planning over
horizons over two to four days, we obtain feasible solutions from both the exact and heuristic
approaches that allow all outgoing trains to leave on time
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