infrastructures Article Structural Evaluation of Variable Gauge Railway Rayhan Usamah 1, Donghoon Kang 2, Youn Doh Ha 3 and Bonyong Koo 1,* 1 Department of Mechanical Engineering, Kunsan National University, 558 Daehak-ro, Gunsan 54140, Korea; [email protected] 2 Railroad Safety Research Team, Korea Railroad Research Institute, 176 Railroad Museum St., Uiwang-si 16105, Korea; [email protected] 3 Department of Naval Architecture and Ocean Engineering, Kunsan National University, 558 Daehak-ro, Gunsan 54150, Korea; [email protected] * Correspondence: [email protected] Received: 13 September 2020; Accepted: 28 September 2020; Published: 1 October 2020 Abstract: In the Eurasian railway network, a different gauge length is used across several countries. A railroad variable gauge allows railway vehicles in rail transport to travel across a gauge break caused by two railway networks with differing track gauges. The variable gauge railway consists of the bogie system to change the length of the wheel shaft and the gauge changing railroad track. Thus, it is important to assess the structural performance of the variable gauge system. In this study, as a performance improvement subject of the variable gauge bogie and railroad, a structural analysis using dynamic finite element calculation was performed to evaluate the reliability and life cycle of the release system and the variable gauge railway. First, the contact pressure and structural stress of the release disk and the release rail were calculated, which provided the wear condition and fatigue life prediction of variable gauge components. Second, a structural analysis of the gauge stabilization rail after the gauge release was executed. The maximum principal stress was evaluated to guarantee the required service life of the stabilization rail section. For the operational safety of the variable gauge system, the operation conditions and maintenance requirements of the variable gauge railway were proposed. Keywords: railroad variable gauge system; structural analysis; fatigue life; wear condition 1. Introduction A railway network is comprised of several different gauge lengths for historical reasons: narrow gauge, standard gauge, and broad gauge. Due to this difference in gauge length, conventional trains cannot run on the same track, and consequently, passengers are forced to transfer at intermediate junctions [1]. To avoid transportation difficulties and the cost of different gauge tracks on the trains, a variable gauge system is an efficient solution applied in some countries, such as in the Eurasian railroad network [2,3]. This system effectively replaces time-consuming tasks such as transferring freight, replacing individual wheels and axles, truck exchange, transporters, or transporter flatcars because the systems mentioned above are both time consuming and very costly. Kondo [4] introduced a novel traction control system of the gauge changing train, which can run through two different gauge sections. The Spanish Talgo train, which is operating between Spain and France, is known for its variable system, enabling it to switch between broad (1668 mm) and standard European gauges [5]. Recently a variable gauge wheelset system installed in the bogie was developed and the fatigue strength of the system was investigated [6,7]. A life cycle cost model was developed to assess the effectiveness of a variable gauge system [8]. Several factors can influence fatigue life, including loading history, stress state, strain rate, and temperature, and can lead under certain conditions (like low temperature) to brittle fracture [9,10]. Failure of a component can have catastrophic Infrastructures 2020, 5, 80; doi:10.3390/infrastructures5100080 www.mdpi.com/journal/infrastructures Infrastructures 2020, 5, 80 2 of 14 Infrastructures 2020, 5, x FOR PEER REVIEW 2 of 14 consequences; therefore,therefore, the the study study and and prediction prediction of railroad of railroad failure failure can prevent can prevent loss of lifeloss and of propertylife and damageproperty [damage11–13]. Fatigue[11–13]. crackingFatigue cracking is caused is bycaused cyclic by loads, cyclic although loads, although the resultant the resultant stress level stress is substantiallylevel is substantially below the below material’s the material’s yield strength yield [st14rength]. Besides [14]. fatigue Besides analysis, fatigue other analysis, factors other need factors to be consideredneed to be considered to avoid loss to of avoid life and loss property of life and damage, prop sucherty damage, as wear and such friction. as wear Friction and friction. occurs betweenFriction twooccurs contact between surfaces two in contact relative surfaces motion, whereasin relative wear motion, is the phenomenon whereas wear of mechanicalis the phenomenon and chemical of damagemechanical that and aff ectschemical the quality damage of that the materialsaffects the in quality contact of withthe materials each other in [contact15,16]. Wearwith each of system other components[15,16]. Wearis of often system a critical components factor influencingis often a crit theical product factor influencing service life. the In addition,product service the overhead life. In electricaddition, wire the interactionoverhead electric [17] to transmitwire interaction the electricity [17] to totransmit the railway the electricity vehicle and to the the railway vehicle systemvehicle dynamicsand the vehicle [18] to system reduce dynamics longitudinal [18] oscillations to reduce inlong passengeritudinal trainsoscillations need to in be passenger addressed trains in the need design to ofbe theaddressed wheelset in system.the design of the wheelset system. In this paper, to quantitivelyquantitively evaluate the life of the variable gauge railway, dynamic finitefinite element analysis using Abaqus was executed for for the the release release disk disk and and the the release release rail rail in in Section Section 22.. Between contractingcontracting partsparts of of the the disk disk and and the the rail, rail, there there is limiting is limiting criteria criteria for contact for contact pressure pressure to avoid to wearavoid problems wear problems using the using Archard the Archard formula formula [19,20]. [19,20]. Based on Based the finite on the element finite simulationelement simulation and the wear and criteriathe wear of criteria the contacting of the contacting surface, the surface, safe operating the safe velocity operating and velocity the fatigue and issues the fatigue of the release issues dickof the in therelease variable dick gaugein the systemvariable were gauge proposed system withwere an pr emphasisoposed with on thean lubricationemphasis on of the the lubrication contact surface of the to minimizecontact surface friction to andminimize to reduce friction mechanical and to reduce wear. Inmechanical Section3, thewear. fatigue In Section life of 3, the the grooved fatigue raillife inof the grooved variable rail gauge in the railway variable during gauge the railway gauge duri changingng the operation gauge changing is estimated operation from is the estimated load history from ofthe the load multi-body history of dynamicthe multi-body analysis. dynamic Through analysis. fatigue Through life assessment fatigue life by structuralassessment stress by structural analysis, thestress designed analysis, release the designed rail and the release grooved rail railand in the the grooved variable gaugerail in systemthe variable are guaranteed gauge system to be safeare inguaranteed the sense to of be metal safe fatigue in the ifsense continuous of metal maintenance fatigue if continuous procedures maintenance such as surface procedures lubrication such and as inspectionsurface lubrication are applied and adequately. inspection are applied adequately. 2. Structural Analysis of Variable Gauge Release Rail To performperform the the gauge gauge transformation transformation from from the the standard-gauge standard-gauge railway railway with with 1435 mm1435 track mm gaugetrack togauge broad to gaugebroad railwaygauge railway with 1520 with mm 1520 track mm gauge, track ga theuge, release the release disk is disk installed is installed on the bogieon the gauge, bogie andgauge, the and locked the statelocked of state the bogieof the axle bogie is releasedaxle is released by the operatingby the operating principle principle that the that release the release disk is pusheddisk is pushed in contact in contact with the with release the release rail when rail when the bogie the bogie is advancing. is advancing. The The variable variable gauge gauge system system of theof the release release rail rail and and the the release release disk disk in in the the unlocking unlocking section section is is illustrated illustrated in in FigureFigure1 1.. The The unlockingunlocking section of the variable gauge railroad ofof 23802380 mmmm lengthlength isis shownshown inin FigureFigure2 2.. Figure 1. VariableVariable gauge system of releaserelease rail and release disk. Infrastructures 2020, 5, x FOR PEER REVIEW 3 of 14 Infrastructures 2020, 5, 80 3 of 14 Infrastructures 2020, 5, x FOR PEER REVIEW 3 of 14 Figure 2. Releasing section of the railway track for a variable gauge system. Figure 2. ReleasingReleasing section of the railway track for a variable gauge system. To perform the gauge conversion between standard gauge and broad gauge, a release disk is To perform the gauge conversion between standard gauge and broad gauge, a release disk is installedTo perform on the bogie the gauge