<p>Utvecklingen inom järnvägssektorn går mot snabbare och mer effektiva transporter, dock begränsas utvecklingen av att det krävs nya och mer utvecklade spår och tåg för att uppnå det. Med dagens infrastruktur och tågmodeller är hastigheter på 200 km/h det maximala. Behovet att öka kapaciteten och införa höghastighetstrafik i Sverige utreds i nuläget. Med höghastighetstrafik avses hastigheter på minst 250 km/h. Banverket har som förvaltare av järnvägen ett sektorsansvar för miljön och således även buller. I och med ökade hastigheter ökar även bullret från tågen. Dessutom uppkommer nya former av buller vid hastigheter över 300 km/h. Det buller som uppstår vid dessa höga hastigheter är så kallat aerodynamiskt buller som kommer av turbulenta luftflöden runt tåget.</p><p>Syftet med examensarbetet har varit att samla in kunskap som finns internationellt angående bulleremissioner och åtgärder mot dessa. Information har samlats in genom en litteraturstudie samt genom personlig kontakt med personer inom den internationella järnvägssektorn. Utifrån kunskapsläget internationellt har en modell skapats med de åtgärder som bedömts viktigast. Tanken med modellen är att ge en bild av de åtgärder mot och källor till bullret som främst kommer av höghastighetstrafik. Men även för att ge Banverket en kompetensgrund att stå på inför en framtida implementering av höghastighetstrafik.</p><p>Bullerskyddsåtgärder som prioriteras internationellt är planeringen om var banan ska dras. Denna åtgärd utreds under planerandefasen vid nybyggnation av bana. I denna fas kan problem likväl skapas som elimineras och det är här som grunden läggs för framtiden. Utvecklingen av tågen och tekniska lösningar som räldämpare, bullerskärmar och optimal design av banunderbyggnaden är även det prioriterade områden inom höghastighetstrafiken internationellt. Då är det främst utveckling av tekniska lösningar för att minimera det aerodynamiska buller som uppkommer samt buller från kontakten mellan hjul och räl.</p><p>Den generella arbetsgången är att fokus ligger på åtgärder mot källbullret. Därefter prioriteras åtgärder som ligger längs ljudutbredningsvägen och sist kommer de åtgärder som tillämpas vid mottagaren av bullret.</p> / <p>The development within the railway sector is heading towards faster and more effective transports. The limitations are that new developments must be applied on the trains as well as the tracks. With the infrastructure and train models that we have today, speeds up to 200 km/h is the maximum speed. The needs to raise the capacity and implement high-speed trains in Sweden are under investigation. The speed of the trains must exceed 250 km/h to be labeled as high-speed trains. Banverket as the infrastructure manager has a responsibility for the environment and the noise pollution created by train traffic. As the speed increases so does the noise as well, but it is also new forms of noise that appear with speeds over 300 km/h. The noise that appears around these velocities is called aerodynamic noise and it is coming from the turbulence in the air around the train.</p><p>The aim of the thesis has been to gather knowledge internationally on the issues concerning noise emissions and measures to prevent them. The information has been gathered thorough a literature survey and by interviews with people within the international railway sector. By the inventory of the knowledge a model has been developed with the issues that are judged to be the most important. The idea with the model is to give a picture of the measures to prevent the noise and sources of the noise that are coming from high-speed traffic. It is also made for Banverket to get the competence to deal with a future implementation of high-speed traffic.</p><p>A noise preventive measures that is prioritized internationally is planning the localization of the track. This measure is treated during the land use planning when a new line should be built. In this phase problems can either be created or eliminated and it is here the foundation is built for the future. The development of the trains and technical solutions such as rail dampers, noise screens and optimal track design are also measures that have high priority internationally. It is mainly the development and the technical solutions to minimize the aerodynamic noise that occurs and also the noise that are emitted from the contact between the wheels and the rail.</p><p>The general working process is that the focus is on reducing the noise from the source. After that the priority is to minimize the noise along the propagation path and at last measures at the recipient.</p>

This study defines the information gathering and communication and response needed for safety at highway-rail crossings. It examines technologies for low-cost, high-safety treatments for low volume highway crossings of higher speed (130-200 kph) rail. Crossing closure and consolidation is a necessary first step. Existing train control and crossing safety systems are examined. Intelligent Transportation System technologies are examined for applicability to the information gathering, communicating, and control functions of grade crossing safety. Guidelines are offered for low volume crossings of the high speed rail line in Oregon. A preliminary cost benefit analysis is presented. Above 200kph, crossing closure or grade separation is required. In the range of 130-200 kph, ITS technologies have the potential to enhance crossing safety at much lower cost than grade separation. A global positioning system based positive train control system provides the train location and speed information needed for advanced crossing control. A traffic management center can receive train and crossing information, operate crossing systems, and grant clearance for train or highway users through the crossing. Remote lock gates provide safety at private crossings. Increased traveler information and four quadrant warning gates increase motorist compliance at public crossings. At train speeds above 175 kph, barrier gates protect rail movements. Video monitoring and detection systems provide reliable, redundant information should a vehicle become trapped in a crossing. / Graduation date: 1996

The primary objective of this work was to develop a laser source for fundamental investigations in the field of laser – materials interactions. In particular it is supposed to facilitate the study of the influence of the temporal energy distribution such as the interaction between adjacent pulses on ablation processes. Therefore, the aim was to design a laser with a highly flexible and easily controllable temporal energy distribution. The laser to meet these demands is an SBS-laser with optional active mode-locking. The nonlinear reflectivity of the SBS-mirror leads to a passive Q-switching and issues ns-pulse bursts with µs spacing. The pulse train parameters such as pulse duration, pulse spacing, pulse energy and number of pulses within a burst can be individually adjusted by tuning the pump parameters and the starting conditions for the laser. Another feature of the SBS-reflection is phase conjugation, which leads to an excellent beam quality thanks to the compensation of phase distortions. Transverse fundamental mode operation and a beam quality better than 1.4 times diffraction limited can be maintained for average output powers of up to 10 W. In addition to the dynamics on a ns-timescale described above, a defined splitting up of each ns-pulse into a train of ps-pulses can be achieved by additional active mode-locking. This twofold temporal focussing of the intensity leads to single pulse energies of up to 2 mJ at pulse durations of approximately 400 ps which corresponds to a pulse peak power of 5 MW. While the pulse duration is of the same order of magnitude as those of other passively Q-switched lasers with simultaneous mode-locking, the pulse energy and pulse peak power exceeds the values of these systems found in the literature by an order of magnitude. To the best of my knowledge the laser presented here is the first implementation of a self-starting mode-locked SBS-laser oscillator. In order to gain a better understanding and control of the transient output of the laser two complementary numerical models were developed. The first is based on laser rate equations which are solved for each laser mode individually while the mode-locking dynamics are calculated from the resultant transient spectrum. The rate equations consider the mean photon densities in the resonator, therefore the propagation of the light inside the resonator is not properly displayed. The second model, in contrast, introduces a spatial resolution of the resonator and hence the propagation inside the resonator can more accurately be considered. Consequently, a mismatch between the loss modulation frequency and the resonator round trip time can be conceived. The model calculates all dynamics in the time domain and therefore the spectral influences such as the Stokes-shift have to be neglected. Both models achieve an excellent reproduction of the ns-dynamics that are generated by the SBS-Q-switch. Separately, each model fails to reproduce all aspects of the ps-dynamics of the SBS-laser in detail. This can be attributed to the complexity of the numerous physical processes involved in this system. But thanks to their complementary nature they provide a very useful tool for investigating the various influences on the dynamics of the mode-locked SBS-laser individually. These aspects can eventually be recomposed to give a complete picture of the mechanisms which govern the output dynamics. Among the aspects under scrutiny were in particular the start resonator quality which determines the starting condition for the SBS-Q-switch, the modulation depth of the AOM and the phonon lifetime as well as the Brillouin-frequency of the SBS-medium. The numerical simulations and the experiments have opened several doors inviting further investigations and promising a potential for further improvement of the experimental results: The results of the simulations in combination with the experimental results which determined the starting conditions for the simulations leave no doubt that the bandwidth generation can primarily be attributed to the SBS-Stokes-shift during the buildup of the Q-switch pulse. For each resonator round trip, bandwidth is generated by shifting a part of the revolving light in frequency. The magnitude of the frequency shift corresponds to the Brillouin-frequency which is a constant of the SBS material and amounts in the case of SF6 to 240 MHz. The modulation of the AOM merely provides an exchange of population between spectrally adjacent modes and therefore diminishes a modulation in the spectrum. By use of a material with a Brillouin-frequency in the GHz range the bandwidth generation can be considerably accelerated thereby shortening the pulse duration. Also, it was demonstrated that yet another nonlinear effect of the SBS can be exploited: If the phonon lifetime is short compared to the resonator round trip time we obtain a modulation in the SBS-reflectivity that supports the modulation of the AOM. The application of an external optical feedback by a conventional mirror turns out to be an alternative to the AOM in synchronizing the longitudinal resonator modes. The interesting feature about this system is that it is ― although highly complex in the physical processes and the temporal output dynamics ― very simple and inexpensive from a technical point of view. No expensive modulators and no control electronics are necessary. Finally, the numerical models constitute a powerful tool for the investigation of emission dynamics of complex laser systems on arbitrary timescales and can also display the spectral evolution of the laser output. In particular it could be demonstrated that differences in the results of the complementary models vanish for systems of lesser complexity. / Ziel der Arbeit ist die Entwicklung einer Laserstrahlquelle, die zur Untersuchung von Laser-Material-Wechselwirkungen eingesetzt werden soll. Im Mittelpunkt des Interesses steht hierbei der Einfluss der zeitlichen Pulsstruktur des Lasers auf Materialabtragsprozesse. Daraus ergibt sich die Anforderung einer möglichst hohen Flexibilität in der Pulsstruktur des Lasers sowie einer möglichst guten Strahlqualität. Eine gute Strahlqualität zeichnet sich durch eine homogene räumliche Intensitätsverteilung aus und ist Voraussetzung für eine gezielte Energiedeponierung auf dem Material. Diese Anforderungen wurden mit einem SBS-Laser erfüllt. Dabei handelt es sich um einen Laser, der einen SBS-Spiegel verwendet, dessen Reflektivität auf der Streuung des Lichts an Schallwellen beruht, die von dem einfallenden Licht selbst erzeugt werden. Als Resultat hat dieser Spiegel eine Reflektivität, die abhängig von der Energie des eingestrahlten Lichts ist. In einem Laser verwendet führt diese energieabhängige Reflektivität zu einer sogenannten Güteschaltung, die sich in der Ausbildung von kurzen Lichtpulsen mit Dauern von etwa 100 Nanosekunden äußert. Die Abstände zwischen den Pulsen, die Pulsdauern und die Pulsenergien können sehr leicht durch die Randbedingungen, wie etwa die Reflektivität der konventionellen Spiegel des Lasers, gesteuert werden. Durch eine zusätzliche, aktiv herbeigeführte Verlustmodulation im Laserresonator wird eine Aufspaltung der Nanosekundenpulse in eine Reihe von Pulsen mit Dauern von nur noch einigen 100 Pikosekunden erreicht. Diese Technik ist unter dem Begriff Modenkopplung bekannt. Es liegt jetzt also eine doppelte Pulsstruktur vor: Nanosekundenpulse, die sich jeweils aus vielen Pikosekundenpulsen zusammensetzen. Durch diese doppelte zeitliche Bündelung der Ausgangsleistung werden während der Pulse Spitzenleistungen von bis zu 5 MW erreicht. Die Pulsenergien der ps-Pulse erreichen bis zu 2 mJ. Diese Werte liegen um den Faktor 10 über denen vergleichbarer Systeme. Meines Wissens ist dies die erste Umsetzung eines selbsttätigen SBS-Lasers mit zusätzlicher Modenkopplung. Um die verschiedenen Einflüsse auf diese Emissionsdynamik besser verstehen und kontrollieren zu können, wurden zwei Modelle mit komplementären Ansätzen entwickelt, auf deren Basis diese Dynamik durch numerische Simulationen wiedergegeben werden kann. Insbesondere können auf diese Weise auch die Einflüsse von einzelnen Materialparametern isoliert betrachtet werden, was im Experiment im allgemeinen nicht möglich ist. Der SBS-Laser wurde bereits erfolgreich in Laser-Materialbearbeitungsexperimenten eingesetzt. So konnte beispielsweise gezeigt werden, dass sich die Bearbeitungsdauer beim Wendelbohren durch die Verwendung von Pulszügen, also einer Reihe kurz aufeinander folgender Pulse, gegenüber dem Einsatz von Pulsen mit gleichmäßigen Abständen erheblich verbessern lässt.

The Svealand line opened in 1997 and the services areoperated with regional high speed trains. While the Svealandline was being built, the slow trains that had been inoperation on the old railway between Eskilstuna and Stockholm(a distance of 115 km) were replaced by buses with a highfrequency of service. In a case study of the effects of regional high speed trainservices, field surveys were made of residents and publictransport passengers along the line, and in a reference centreof population, before and after the Svealand line opened.Changes in knowledge, valuations and travel behaviour have beenanalysed, as have changes in accessibility. The supply and thedemand for regional journeys by car, bus and train have alsobeen examined. The results show that the Svealand line has meant anincrease of up to seven times in regional travel by railcompared to the old railway between Eskilstuna and Stockholm,and the market share has risen from 6% to 30%. Those who travelmost are people who have access to a car at times. Habitualmotorists, on the other hand, account for the largest increasein travel by public transport. In areas close to the railwaystations in Strängnäs and Eskilstuna new patterns ofcar ownership, travel behaviour, choice of transport mode andchoice of destination have been found since the regional highspeed trains began operating on the Svealand line. Commuting towork has also shown a marked increase. Travelling times arevalued highly and especially motorists value the high speedtrain mode of transport highly. Poorer train services and busservices are not attractive to motorists other than as areserve alternative to their own cars. A general conclusion is that the regional high speed trainservices have had a major impact on the travel market, travelbehaviour and accessibility. The improved accessibility toStockholm in particular is especially noticeable amongresidents close to the railway stations. Keywords:The Svealand line, high speed trains, regionaltravel, travel behaviour, choice of transport mode,accessibility / QC 20100608

Carbody tilting is today a mature and inexpensive technology that allows higher train speeds in horizontal curves, thus shortening travel time. This doctoral thesis considers several subjects important for improving the competitiveness of tilting trains compared to non-tilting ones. A technology review is provided as an introduction to tilting trains and the thesis then focuses on enhancing the benefits and strategies for less motion sickness. A tilting train may run about 15% faster in curves than a non-tilting one but the corresponding simulated running time benefit on two Swedish lines is about 10%. The main reason for the difference is that speeds are set on other grounds than cant deficiency at straight track, stations, bridges, etc. The possibility to further enhance tilting trains’ running speed is studied under identified speed limitations due to vehicle-track interaction such as crosswind requirements at high speed curving. About 9% running time may be gained on the Stockholm–Gothenburg (457 km) mainline in Sweden if cant deficiency, top speed, and tractive performance are improved compared with existing tilting trains. Non-tilting high-speed trains are not an option on this line due to the large number of 1,000 m curves. Tilting trains run a greater risk of causing motion sickness than non-tilting trains. Roll velocity and vertical acceleration are the two motion components that show the largest increase, but the amplitudes are lower than those used in laboratory tests that caused motion sickness. Scientists have tried to find models that can describe motion sickness based on one or more motion quantities. The vertical acceleration model shows the highest correlation to motion sickness on trains with active tilt. However, vertical acceleration has a strong correlation to several other motions, which precludes vertical acceleration being pointed out as the principal cause of motion sickness in tilting trains. Further enhanced speeds tend to increase carbody motions even more, which may result in a higher risk of motion sickness. However, means to counteract the increased risk of motion sickness are identified in the present work that can be combined for best effect. Improved tilt control can prevent unnecessary fluctuations in motion sickness related quantities perceived by the passengers. The improved tilt control can also manage the new proposed tilt algorithms for less risk of motion sickness, which constitute one of the main achievements in the present study. Local speed restrictions are another means of avoiding increased peak levels of motion sickness when increasing the overall speed. The improved tilt control and the proposed tilt algorithms have proven to be effective in on-track tests involving more than 100 test subjects. The new tilt algorithms gave carbody motions closer to non-tilting trains. Rather unexpectedly, however, the test case with the largest decrease in tilt gave a greater risk of motion sickness than the two test cases with less reduction in tilt. It is likely that even better results can be achieved by further optimization of the tilt algorithms; the non-linear relation between motions and motion sickness is of particular interest for further study. / QC 20110429

Utvecklingen inom järnvägssektorn går mot snabbare och mer effektiva transporter, dock begränsas utvecklingen av att det krävs nya och mer utvecklade spår och tåg för att uppnå det. Med dagens infrastruktur och tågmodeller är hastigheter på 200 km/h det maximala. Behovet att öka kapaciteten och införa höghastighetstrafik i Sverige utreds i nuläget. Med höghastighetstrafik avses hastigheter på minst 250 km/h. Banverket har som förvaltare av järnvägen ett sektorsansvar för miljön och således även buller. I och med ökade hastigheter ökar även bullret från tågen. Dessutom uppkommer nya former av buller vid hastigheter över 300 km/h. Det buller som uppstår vid dessa höga hastigheter är så kallat aerodynamiskt buller som kommer av turbulenta luftflöden runt tåget. Syftet med examensarbetet har varit att samla in kunskap som finns internationellt angående bulleremissioner och åtgärder mot dessa. Information har samlats in genom en litteraturstudie samt genom personlig kontakt med personer inom den internationella järnvägssektorn. Utifrån kunskapsläget internationellt har en modell skapats med de åtgärder som bedömts viktigast. Tanken med modellen är att ge en bild av de åtgärder mot och källor till bullret som främst kommer av höghastighetstrafik. Men även för att ge Banverket en kompetensgrund att stå på inför en framtida implementering av höghastighetstrafik. Bullerskyddsåtgärder som prioriteras internationellt är planeringen om var banan ska dras. Denna åtgärd utreds under planerandefasen vid nybyggnation av bana. I denna fas kan problem likväl skapas som elimineras och det är här som grunden läggs för framtiden. Utvecklingen av tågen och tekniska lösningar som räldämpare, bullerskärmar och optimal design av banunderbyggnaden är även det prioriterade områden inom höghastighetstrafiken internationellt. Då är det främst utveckling av tekniska lösningar för att minimera det aerodynamiska buller som uppkommer samt buller från kontakten mellan hjul och räl. Den generella arbetsgången är att fokus ligger på åtgärder mot källbullret. Därefter prioriteras åtgärder som ligger längs ljudutbredningsvägen och sist kommer de åtgärder som tillämpas vid mottagaren av bullret. / The development within the railway sector is heading towards faster and more effective transports. The limitations are that new developments must be applied on the trains as well as the tracks. With the infrastructure and train models that we have today, speeds up to 200 km/h is the maximum speed. The needs to raise the capacity and implement high-speed trains in Sweden are under investigation. The speed of the trains must exceed 250 km/h to be labeled as high-speed trains. Banverket as the infrastructure manager has a responsibility for the environment and the noise pollution created by train traffic. As the speed increases so does the noise as well, but it is also new forms of noise that appear with speeds over 300 km/h. The noise that appears around these velocities is called aerodynamic noise and it is coming from the turbulence in the air around the train. The aim of the thesis has been to gather knowledge internationally on the issues concerning noise emissions and measures to prevent them. The information has been gathered thorough a literature survey and by interviews with people within the international railway sector. By the inventory of the knowledge a model has been developed with the issues that are judged to be the most important. The idea with the model is to give a picture of the measures to prevent the noise and sources of the noise that are coming from high-speed traffic. It is also made for Banverket to get the competence to deal with a future implementation of high-speed traffic. A noise preventive measures that is prioritized internationally is planning the localization of the track. This measure is treated during the land use planning when a new line should be built. In this phase problems can either be created or eliminated and it is here the foundation is built for the future. The development of the trains and technical solutions such as rail dampers, noise screens and optimal track design are also measures that have high priority internationally. It is mainly the development and the technical solutions to minimize the aerodynamic noise that occurs and also the noise that are emitted from the contact between the wheels and the rail. The general working process is that the focus is on reducing the noise from the source. After that the priority is to minimize the noise along the propagation path and at last measures at the recipient.

The real phenomena of sea surface are interacting by much kind of different waves.In these phenomena, the gravity standing wave is most important. The gravity standing wave is formed by two progressive waves that possessing same properties but opposite directions. Gravity standing wave can also form by the interaction of a progressive wave with it¡¦s totally reflection wave. Because of the nonlinear interaction of two waves, there must result a double-crest phenomenon of wave pressure. It is dangerous for the navigation of ship when the double-crest appears, and it¡¦s certainly to take the phenomenon into consideration when we are going to design a jetty. In this paper, it bases on the reference of Chen (1989, 1990) who obtained a third-order approximation of two-wave trains interactions in a uniform depth wave field. Further, in this paper, it checks the result that the double-crest phenomenon is formed by which one of these nonlinear terms. Furthermore, research the influences of wave steepness, wave periods, and water depths these factors will cause the crest diverges is also the purpose.

<p>Carbody tilting is today a mature and inexpensive technology allowing higher speeds in curves and thus reduced travel time. The technology is accepted by most train operators, but a limited set of issues still holding back the full potential of tilting trains. The present study identifies and report on these issues in the first of two parts in this thesis. The second part is dedicated to analysis of some of the identified issues. The first part contains Chapters 2 to 5 and the second Chapters 6 to 12 where also the conclusions of the present study are given.</p><p>Chapters 2 and 3 are related to the tilting train and the interaction between track and vehicle. Cross-wind stability is identified as critical for high-speed tilting trains. Limitation of the permissible speed in curves at high speed may be needed, reducing the benefit of tilting trains at very high speed. Track shift forces can also be safety critical for tilting vehicles at high speed. An improved track standard must be considered for high speed curving.</p><p>Chapters 4 and 5 cover motion sickness knowledge, which may be important for the competitiveness of tilting trains. However, reduced risk of motion sickness may be contradictory to comfort in a traditional sense, one aspect can not be considered without also considering the other. One pure motion is not the likely cause to the motion sickness experienced in motion trains. A combination of motions is much more provocative and much more likely the cause. It is also likely that head rotations contribute as these may be performed at much higher motion amplitudes than performed by the train.</p><p>Chapter 6 deals with services suitable for tilting trains. An analysis shows relations between cant deficiency, top speed, tractive performance and running times for a tilting train. About 9% running time may be gained on the Swedish line Stockholm – Gothenburg (457 km) if cant deficiency, top speed and tractive performance are improved compared with existing tilting trains. One interesting conclusion is that a non-tilting very high-speed train (280 km/h) will have longer running times than a tilting train with today’s maximum speed and tractive power. This statement is independent of top speed and tractive power of the non-tilting vehicle.</p><p>Chapters 7 to 9 describe motion sickness tests made on-track within the EU-funded research project<i> Fast And Comfortable Trains (FACT).</i> An analysis is made showing correlation between vertical acceleration and motion sickness. However, vertical acceleration could not be pointed out as the cause to motion sickness as the correlation between vertical acceleration and several other motions are strong.</p><p>Chapter 10 reports on design of track geometry. Guidelines for design of track cant are given optimising the counteracting requirements on comfort in non-tilting trains and risk of motion sickness in tilting trains. The guidelines are finally compared with the applied track cant on the Swedish line Stockholm – Gothenburg. Also transition curves and vertical track geometry are shortly discussed.</p><p>Chapters 11 and 12 discusses the analysis, draws conclusions on the findings and gives proposals of further research within the present area.</p>

published_or_final_version / Transport Policy and Planning / Master / Master of Arts in Transport Policy and Planning

The tractive force has to be interrupted during a gear-shifting operation in a manual vehicle transmission, leading into a decrease of speed while changing gears during the acceleration process. Therefore in a racing application, the shifting time has to be as short as possible so that the required performance of a racing car can be achieved. The following dissertation describes the development of a transmission control system to enable gear changes within a manual gearbox, which was designed for the Formula Student racing series. Various solutions were developed on the basis of reviewed literature, technical data of components and experiences of Formula Student teams. Following this, a comparison of the concepts by means of a utility analysis identified the pneumatic actuation of selector forks to be the most suitable concept. This was mainly due to the expected shifting time, the weight, and its advantageous energy supply requirement. After the selection of the actuators and the position sensors, the system was implemented into the drivetrain to check the tment and the technical feasibility. To draw conclusions regarding the shifting time and to prove the functionality of the system, an open test bench was constructed. Additionally, the hardware and software had to be developed to enable the test run. After the manufacturing and assembling of the test bench, the optimal settings for the test run were determined. By comparing the achieved shifting time of alternative solutions, an improvement in the driving performance of a Formula Student race car is probable.