71 research outputs found
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Assessing the efficient cost of sustaining Britain's rail network: Perspectives based on zonal comparisons
The objective of this paper is to inform the debate on how efficiency targets for Network Rail (formerly Railtrack) should be set during the 2002/03 Interim Review and beyond. Given the problems experienced during the 2000 Periodic Review, which focused on external benchmarks, we propose an internal benchmarking approach, drawing on data for seven geographical Zones within Railtrack (over the period 1995/96 to 2001/02). Our approach mirrors the yardstick competition method used in other UK regulated industries. Three efficiency measurement techniques are applied to this data (DEA; COLS; SFA). Our results suggest that Railtrack (as a whole) delivered substantial improvements in productivity in the early years after privatisation, although these savings were largely offset by the post-Hatfield cost increases. However, looking forward, Zonal efficiency differences suggest that the company could make significant savings in future years by applying (its own) best practice consistently across the network
Estimation of cost inefficiency in panel data models with firm specific and sub-company specific effects
This paper proposes a dual-level inefficiency model for analysing datasets with a sub-company structure, which permits firm inefficiency to be decomposed into two parts: a component that varies across different sub-companies within a firm (internal inefficiency); and a persistent component that applies across all sub-companies in the same firm (external inefficiency). We adapt the models developed by Kumbhakar and Hjalmarsson (J Appl Econom 10:33–47, 1995) and Kumbhakar and Heshmati (Am J Agric Econ 77:660–674, 1995), making the same distinction between persistent and residual inefficiency, but in our case across sub-companies comprising a firm, rather than over time. The proposed model is important in a regulatory context, where datasets with a sub-company structure are commonplace, and regulators are interested in identifying and eliminating both persistent and sub-company varying inefficiency. Further, as regulators often have to work with small cross-sections, the utilisation of sub-company data can be seen as an additional means of expanding cross-sectional datasets for efficiency estimation. Using an international dataset of rail infrastructure managers we demonstrate the possibility of separating firm inefficiency into its persistent and sub-company varying components. The empirical illustration highlights the danger that failure to allow for the dual-level nature of inefficiency may cause overall firm inefficiency to be underestimated
Is the choice of (t-T) in Battese and Coelli (1992) type stochastic frontier models innocuous? Observations and generalisations.
In this paper we consider the sensitivity of functional form in the popular panel data stochastic frontier model proposed by Battese and Battese and Coelli (BC, 1992). We demonstrate that adopting the (t−Tt−T) efficiency functional form used by BC can, in a model which allows for firm specific patterns of temporal inefficiency variation (as developed by Cuesta, 2000), results in counter intuitive ‘falling-off’ of efficient firms in the final sample year. This motivates us to look at a more general parameterisation. First we show that the choice of a function within the first order exponential class is only an issue for the Cuesta model; in the BC model, parameter estimates and inefficiency estimates are invariant to the form. Second we apply the more general model to a railways dataset and find that this model does not seem to suffer from the most efficient firms falling off the frontier. We discuss how to test restrictions in order to make the model more parsimonious, thus preserving the attractive property of the Cuesta model, namely the ability to test for firm specific patterns of inefficiency variation
Benchmarking of Train Operating Companies – A Transaction Cost Efficiency Analysis
Benchmarking of rail firms has become a matter of substantial interest and many authors have emphasised the importance of transaction costs in regard to assessing the desirability of vertical separation. However, due to data and methodological limitations, previous rail efficiency studies have been unable to explicitly analyse the role that transaction cost measures play in determining the relative efficiency performance of different rail firms or rail systems. This paper incorporates recently-produced measures of transaction costs (Merkert 2008) into a two-stage bootstrapped data envelopment analysis (DEA), applied to a sample of 43 Swedish, German and British train operating firms. In the first stage, the number of transaction staff is included as a separate (physical) input within the DEA. This is followed by a second-step Tobit regression which seeks to evaluate the impact of institutional (vertical separation and type of operation), environmental (competition) and transactional (monetary values of transaction costs) factors on technical efficiency. The results of the analysis show that transactional factors are more important in determining technical efficiency than institutional factors and the opening-up of competition
Estimating the marginal cost of railway track renewals using corner solution models
Economic theory advocates marginal cost pricing for efficient utilisation of transport infrastructure. A growing body of literature has emerged on the issue of rail marginal infrastructure wear and tear costs, but the majority of the work is focused on costs for infrastructure maintenance. Railway track renewals are a substantial part of an infrastructure manager’s budget, but in disaggregated statistical analyses they cause problems for traditional regression models since there is a piling up of values of the dependent variable at zero. Previous econometric work has sought to circumvent the problem by aggregation in some way. In this paper we instead apply corner solution models to disaggregate (track-section) data, including the zero observations. We derive track renewal cost elasticities with respect to traffic volumes and in turn marginal renewal costs using Swedish railway renewal data over the period 1999–2009. This paper is the first attempt in the literature to apply corner solution models, and in particular the two-part model, to disaggregate renewal cost data in railways. It is also the first paper that we are aware of to report usage elasticities specifically for renewal costs and therefore adds important new evidence to the previous literature where there is a paucity of studies on renewals and considerable uncertainty over the effects of rail traffic on renewal costs. In the Swedish context, we find that the inclusion of marginal track renewal costs in the track access pricing regime, which currently only reflects marginal maintenance costs, would add substantially to the existing track access charge. EU legislation requires that access charges reflect the ‘costs directly incurred as a result of operating the train service’, which should include a marginal renewal cost component. This change would also increase the cost recovery ratio of the Swedish infrastructure manager, thus meeting a policy objective of the national government
Calibration of photomultiplier arrays
A method is described that allows calibration and assessment of the linearity of response of an array of photomultiplier tubes. The method does not require knowledge of the photomultiplier single photoelectron response model and uses science data directly, thus eliminating the need for dedicated data sets. In this manner all photomultiplier working conditions (e.g. temperature, external fields, etc.) are exactly matched between calibration and science acquisitions. This is of particular importance in low background experiments such as ZEPLIN-III, where methods involving the use of external light sources for calibration are severely constrained
Measurement and simulation of the muon-induced neutron yield in lead
A measurement is presented of the neutron production rate in lead by high energy cosmic-ray muons at a depth of 2850 m water equivalent (w.e.) and a mean muon energy of 260 GeV. The measurement exploits the delayed coincidences between muons and the radiative capture of induced neutrons in a highly segmented tonne scale plastic scintillator detector. Detailed Monte Carlo simulations reproduce well the measured capture times and multiplicities and, within the dynamic range of the instrumentation, the spectrum of energy deposits. By comparing measurements with simulations of neutron capture rates a neutron yield in lead of (View the MathML source) ×10-3 neutrons/muon/(g/cm2) has been obtained. Absolute agreement between simulation and data is of order 25%. Consequences for deep underground rare event searches are discussed
Morphometric differences of Microgramma squamulosa (Kaulf.) de la Sota (Polypodiaceae) leaves in environments with distinct atmospheric air quality
Railway-induced ground vibrations – a review of vehicle effects
This paper is a review of the effect of vehicle characteristics on ground- and track borne-vibrations from railways. It combines traditional theory with modern thinking and uses a range of numerical analysis and experimental results to provide a broad analysis of the subject area. First, the effect of different train types on vibration propagation is investigated. Then, despite not being the focus of this work, numerical approaches to vibration propagation modelling within the track and soil are briefly touched upon. Next an in-depth discussion is presented related to the evolution of numerical models, with analysis of the suitability of various modelling approaches for analysing vehicle effects. The differences between quasi-static and dynamic characteristics are also discussed with insights into defects such as wheel/rail irregularities. Additionally, as an appendix, a modest database of train types are presented along with detailed information related to their physical attributes. It is hoped that this information may provide assistance to future researchers attempting to simulate railway vehicle vibrations. It is concluded that train type and the contact conditions at the wheel/rail interface can be influential in the generation of vibration. Therefore, where possible, when using numerical approach, the vehicle should be modelled in detail. Additionally, it was found that there are a wide variety of modelling approaches capable of simulating train types effects. If non-linear behaviour needs to be included in the model, then time domain simulations are preferable, however if the system can be assumed linear then frequency domain simulations are suitable due to their reduced computational demand
Projected sensitivities of the LUX-ZEPLIN experiment to new physics via low-energy electron recoils
LUX-ZEPLIN is a dark matter detector expected to obtain world-leading sensitivity to weakly-interacting massive particles interacting via nuclear recoils with a
∼
7
-tonne xenon target mass. This paper presents sensitivity projections to several low-energy signals of the complementary electron recoil signal type: 1) an effective neutrino magnetic moment, and 2) an effective neutrino millicharge, both for
p
p
-chain solar neutrinos, 3) an axion flux generated by the Sun, 4) axionlike particles forming the Galactic dark matter, 5) hidden photons, 6) mirror dark matter, and 7) leptophilic dark matter. World-leading sensitivities are expected in each case, a result of the large 5.6 t 1000 d exposure and low expected rate of electron-recoil backgrounds in the
<
100
 
 
keV
energy regime. A consistent signal generation, background model and profile-likelihood analysis framework is used throughout
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