machines Article Numerical and Experimental Characterization of a Railroad Switch Machine Dario Croccolo, Massimiliano De Agostinis, Stefano Fini * ID , Giorgio Olmi and Francesco Robusto ID Department of Industrial Engineering, University of Bologna, Viale del Risorgimento 2, 40136 Bologna, Italy; [email protected] (D.C.); [email protected] (M.D.A.); [email protected] (G.O.); [email protected] (F.R.) * Correspondence: stefano.fi[email protected]; Tel.: +39-051-2093455 Received: 15 January 2018; Accepted: 12 February 2018; Published: 17 February 2018 Abstract: This contribution deals with the numerical and experimental characterization of the structural behavior of a railroad switch machine. Railroad switch machines must meet a number of safety-related conditions such as, for instance, exhibiting the appropriate resistance against any undesired movements of the points due to the extreme forces exerted by a passing train. This occurrence can produce very high stress on the components, which has to be predicted by designers. In order to assist them in the development of new machines and in defining what the critical components are, FEA models have been built and stresses have been calculated on the internal components of the switch machine. The results have been validated by means of an ad-hoc designed experimental apparatus, now installed at the facilities of the Department of Industrial Engineering of the University of Bologna. This apparatus is particularly novel and original, as no Standards are available that provide recommendations for its design, and no previous studies have dealt with the development of similar rigs. Moreover, it has wide potential applications for lab tests aimed at assessing the safety of railroad switch machines and the fulfilment of the specifications by many railway companies. Keywords: railroad switch; railway junction; FEA; experimental; points 1. Introduction A railroad switch machine (RSM), turnout or set of points is a mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off. One of the key safety requirements of railroad switches is related to achieving a suitable resistance against any undesired movements of the points, due, for instance, to the extreme forces exerted by a passing train in the case of the needle leaned to the rail (force F in Figure1). Many railway companies assume a force F = 100 kN as standard. This work deals with the development of FEA models aimed at accomplishing the structural design of the RSM under the aforementioned operating load. In order to validate such models, an experimental test bench has been designed and manufactured. This comprises two ad-hoc designed fixtures that allow the accommodation of the test piece on a standard INSTRON 8500 500 kN standing press and the application of forces up to a maximum of F = 300 kN. Issues of novelty arise from the lack of studies both in the scientific and in the technical literature dealing with the development of similar fixture devices. The developed testing rig can be used not only for FEA validation purposes, but also for experimental tests aimed at warranting the safety of the RSM and the accomplishment of design requirements by most railway companies. The originality of the performed non-trivial design task arises also from the lack of specific Standards providing recommendations or reference schemes for the execution of lab tests aimed at assessing the structural response of RSM under high loads. Machines 2018, 6, 6; doi:10.3390/machines6010006 www.mdpi.com/journal/machines Machines 2018, 6, 6 2 of 9 Machines 2018, 6, x FOR PEER REVIEW 2 of 9 Machines 2018, 6, x FOR PEER REVIEW 2 of 9 FigureFigure 1. 1.Geometry Geometry of of a a railroad railroad switch switch.. Figure 1. Geometry of a railroad switch. 2. Materials and Methods 2. Materials and Methods 2. Materials and Methods The Alstom RSM object of the present investigation is shown in Figure 2, along with some balloonsThe AlstomThe highlightingAlstom RSM RSM object the object k ofey the structuralof presentthe present components investigation investigation of the is shown machine.is shown in Figure in Figure2, along 2, along with with some some balloons highlightingballoons highlighting the key structural the key componentsstructural components of the machine. of the machine. Figure 2. 3d model of the Alstom RSM: (1) body; (2) lower plate; (3) pin; (4) hammer; (5) switching FigurerodFigure 2.; (3d6) 2cam. model 3d; model(7) ofdetection the of the Alstom rodAlstom; (8 RSM:) armRSM:. ( 1 )(1 body;) body (2; )(2 lower) lower plate; plate; ( 3(3)) pin; pin; ((44)) hammer;hammer; ( 5)) switching switching rod; (6) cam;rod;( (76)) detectioncam; (7) detection rod; (8) rod arm.; (8) arm. 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