| 1. |
- Brännlund, Ulf, et al.
(författare)
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Railway Timetabling Using Lagrangian Relaxation
- 1998
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Ingår i: Transportation Science. - : Institute for Operations Research and the Management Sciences (INFORMS). - 0041-1655 .- 1526-5447. ; 32:4, s. 358-369
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Tidskriftsartikel (refereegranskat)abstract
- We present a novel optimization approach for the timetabling problem of a railway company, i.e., scheduling of a set of trains to obtain a profit maximizing timetable, while not violating track capacity constraints. The scheduling decisions are based on estimates of the value of running different types of service at specified times. We model the problem as a very large integer programming problem. The model is flexible in that if allows for general cost functions. We have used a Lagrangian relaxation solution approach, in which the track capacity constraints are relaxed and assigned prices, so that the problem separates into one dynamic program for each physical train. The number of dual variables is very large. However, it turns out that only a small fraction of these are nonzero, wh ich one may take advantage of in the dual updating schemes. The approach has been, tested on a realistic example suggested by the Swedish National Railway Administration. This example contains 18 passenger trains and 8 freight trains to be scheduled during a day on a stretch of single track, consisting of 17 stations. The computation times are rather modest and the obtained timetables are within a few percent of optimality.
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| 2. |
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| 3. |
- Hansson, Lars, et al.
(författare)
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A new Swedish Railroad Policy : Separation of Infrastructure and Traffic Production
- 1991
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Ingår i: Transportation Research Part A. - : Elsevier BV. - 0965-8564 .- 1879-2375 .- 0191-2607. ; 25:4, s. 153-159
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Tidskriftsartikel (refereegranskat)abstract
- In 1988 the Swedish nationalized railway company was separated into two separate entities, the Swedish State Railways in charge of running rail transport and the National Rail Administration, responsible for investment in and maintenance of rail infrastructure. This paper describes institutional aspects of this new railway policy. It also specifies methodological and practical problems in the computation of social marginal costs for using rail as well as road infrastructure. It is furthermore made likely that present fuel charges on road vehicles, but not the new rail use charges, are insufficient to cover costs for infrastructure use.
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| 4. |
- Nilsson, Jan-Eric, 1952-
(författare)
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Allocation of track capacity : Experimental Evidence on the Use of Priority Auctioning in the Railway Industry
- 1999
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Ingår i: International Journal of Industrial Organization. - : Elsevier. - 0167-7187 .- 1873-7986. ; 17:8, s. 1139-1162
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Tidskriftsartikel (refereegranskat)abstract
- Allocation of track capacity concerns multiple users facing demand indivisibilities, running trains over an inelastic supply of railway tracks. The paper suggests a Vickrey-type mechanism to handle incentive aspects of this technically complex optimisation task. Here, the price for operating a train will correspond to the bids foregone by other operators who are pushed off their preferred routes. The paper reports the results of 11 experimental markets using variations of this mechanism where each market includes up to 10 trading periods, and subjects bid for routes over a highly stylised railway network. The experiments generated solutions that capture 90–100% of potential benefits.
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| 5. |
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| 6. |
- Nilsson, Jan-Eric
(författare)
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Behövs mer infrastruktur?
- 1990
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Ingår i: Ekonomisk Debatt. - : Nationalekonomiska föreningen. - 0345-2646. ; :8, s. 777-780
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 7. |
- Nilsson, Jan-Eric, 1952-
(författare)
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Efficiency Implications of Innovations in Administering TransportInfrastructure
- 1997
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This dissertation is concerned with issues directly and indirectly associated with reform of the way that transport infrastructure is managed. It consists of four separate papers. The dissertation summary also provides a unified framework for the otherwise self-contained papers. In abstract, the papers have the following content.Dissertation summary. The unifying framework emphasises information aspects of institutional reform in the transport infrastructure sector. Incomplete and asymmetric information in conjunction with a risk that public sector officials may pursue objectives other than what they are instructed to follow, may have implications for how activities should be organised. It is suggested that this may explain why responsibility for road infrastructure is organisationally separated between a ministry of finance (charging levels) and a ministry of transport or alternatively a road administration (spending decisions).Private Funding of Public Investments. A Case of a Voluntarily Funded Public Road. This paper deals with a government authority facing appropriations that are insufficient to make the construction of all welfare improving investments possible. Some private agent offers the authority a specified amount of money (less than 100 per cent of total costs) in order to implement a project that would otherwise not be built. Accepting this offer means that investments with superior rates of return would be crowded out from the initial plan. The paper demonstrates the conditions under which it is still welfare improving for the authority to accept such offers. Furthermore, the consequences of systematically introducing private contributions as a complementary way to fund public investments on a voluntary basis are considered. The importance of information for these conclusions are also discussed.Investment Decisions in a Public Bureaucracy. A Case Study of Swedish Road Planning Practices. The paper handles the problem of settling a socially relevant ranking of investment projects in the presence of budgetary restrictions and incomplete information about investment benefits and costs. An actual road investment programme, settled under these conditions, is analysed using a binomial logit model. Observed behaviour cannot be shown to be other than partially compatible with social welfare maximising principles.Second Best Problems in Railway Infrastructure Pricing and Investment. In 1988 the Swedish nationalised railway company was separated into the State Railways, in charge of running rail transport, and the National Rail Administration, responsible for investment in, and maintenance of rail infrastructure. The separation made it obvious that the long discussion of optimal road pricing schemes is also relevant for rail traffic. This paper analyses optimal pricing of rail infrastructure use, and optimality conditions for rail and road investment, in a situation where road transport is not charged for its full social marginal costs. It is demonstrated that under most circumstances rail charges should then be below marginal costs and that investments in both modes should be reduced below first best levels. Allocation of Track Capacity. Experimental Evidence on the Use of Priority Auctioning in the Railway Industry.Allocation of track capacity concerns multiple users with demand indivisibilities who run trains over an inelastic supply of railway tracks. Moreover, the individual operators’ value-of-access to tracks is their private information. The paper suggests a Vickrey-type mechanism to handle incentive aspects of this technically complex optimisation problem: The price for operating a train should correspond to the bids foregone by other operators who are pushed off their preferred routes. During eleven experimental markets using variations of this mechanism, each market including up to 10 trading periods, subjects bid for routes over a highly stylised railway network. The experiments have generated solutions that capture 90-100% of the surplus of value-maximising allocations.
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