Recent in situ observations during Critical Ionization Velocity (CIV) experiments under the CRIT project produced puzzling results, apparently at odds with current ClV theories. It is shown that incorporation in the theory of lower hybrid wave (LHW) instabilities of strong turbulence and finite size effects results in reconciliation of the theory with the observations.

July-August 2012 Imagine you fly home from vacation with your one-and-ahalf-year-old son who is traveling for free as a “lap child.” In the airport parking lot, you put him into his forwardfacing car seat, where he sits much more contentedly than he did in the rear-facing one that was mandatory until his first birthday. After he falls asleep on the way home, you transfer him to his crib without...

in this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. two parallel rails of the track have been modeled as euler-bernoulli beams on elastic points as rail pads. also sleepers have been modeled as visco-elastic euler-bernoulli beams. it is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. the...

This paper deals with the threshold radius that warrants the use of single restraining rail for transit and railroads. Different railways use different threshold radius from 91m to 365m to provide restraining rail. These threshold figures are probably experience driven choices. The need for restraining rail may be related to a so-called derailment alarm coefficient of 1.2 sustained over 2m leng...

7 This paper proposes a three-stage game-theoretic model to study air-rail competition in intercity 8 passenger corridors. We consider duopolistic markets, in which a rail agency competes against an airline to 9 maximize their respective objectives. The objective of the rail agency can be maximizing profit or social welfare, 10 or a mix of the two. At the top stage, the rail agency first determ...

the track stiffness experienced by a train will vary along the track. sometimes the stiffness variation may be very large within a short distance. one example is when an unsupported sleeper is hanging in the rail. track stiffness is then, locally at that sleeper, very low. at insulated joints the bending stiffness of the rail has a discontinuity implying a discontinuity also of the track stiffn...

Rail inspection is an important task in railway maintenance. The speed and loads of trains have been increasing greatly in recent years, and these factors inevitably raise the risk of producing rail defects. Mainly the discrete surface defects impact the riding quality and safety of a railway system. However, it is a challenge to inspect such defects in a vision system because of illumination i...

Rail joints have a shorter service life than most other railway track components. The discontinuity between rail ends turns the rail joint into a weak spot, and consequently, into a track component demanding more frequent maintenance measures, which result in high maintenance costs. Moreover, difficulties are often found when assessing the damage condition of rail joints since damage conditions...

Wheel/rail contact simulation is one of the most complicated problems in the modeling of railway vehicles. The wheel/rail interaction plays a unique role in rail vehicle dynamics. In this paper, the dynamic response of the wheel on irregular rail track is analyzed with analytical approach using the method of Multiple Scales (MMS). The Hertzian contact theory is used to obtain the relationshi...