simulation of torsion moment at the wheel set of the railway vehicle ...

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3. Intermodal trainsIntermodal trains are taken as a system of fast train connectionsof intermodal transport (hereinafter as IMT) which ensuresconnection among individual IMT terminals in desired quality andsufficient volume of transported goods. Systems of through trainsand mixed trains are used for the train connection among IMT terminals.From the railway carrier’s point of view the whole cargo(transport unit) is transported either as an individual set of coachesor as a group of sets of coaches or as the shuttle train. The biggestshare of IMT cargos is transported in the shuttle trains which allbelong to the “Nex” train category.Heinrici [11] found that the systems of train connections ofIMT transport units can be operated on an individual line or ona specified line network. In the former case we speak of so-called“line system” and in the latter case we speak of the so-called“network system”.The network system of train connections is characterized asa network service of individual terminals on a specified trafficnetwork. This means that there is a gap in the service of individualIMT terminals using line systems which are included in the trafficnetwork. A system of shuttle trains connecting the individual IMTterminals is usually used in the network system. This networksystem is in the IMT area represented by the “Hub-and-Spoke”system, as described by Novak [21].this technology is used mainly abroad. For example, in Germany(IMT operator Kombiverkehr) this system is represented as the“goods IC-concept”. It is a very similar system to the one used bypassenger trains IC, ICE and EC categories, as described byHeinrici [11].A practical application of this technology has been found notonly abroad but also in the Czech Republic. Especially in transportationamong seaports (Rotterdam, Bremerhaven, Hamburg)and some inland terminals (Praha-Uhrineves, Melník, Lovosice)that have the position of node terminals. In these lines the freighttraffic volumes are high and the trains are usually set out twice perday (24 hours). In other sequential directions (other terminals inthe CR or adjacent countries) the freight traffic volumes are muchlower and the train set-out frequency is much lower (2 to 5 trainsper week).4. Train routes model for intermodal trainsThe task of any transport problem solved by a mathematicmodel is finding its attributes, analysing all its states and verifyingits scheduled parameters. This is subjected to right definition anddimensioning of system items, efficient regulation and organizationof the system.4.1 General solutionIn the node terminal two groups of shipments are assembledfor one train. Cerna [4] and Janacek [13] suggest that in the firstgroup are shipments which enter the system in that node. Thesecond group are shipments which came into that node by train.If there is a node u in time t ij (arrival time of train j on line i) , theshipment will be brought by train sij on train path L i , will bereloaded for time l (time of reload from line i to lane r) to positionon train path L r and will wait for the nearest train s rg of thattrain path with the depart at time t rg (departure time of train g online r):trg $ tij + tirl[min] (1)Providing that the train s ij departs from a starting station attime t o ij and that the travelling time to node u is d u ij then the arrivaltime to t ij can be formularized by 2 and 3:t ijo= t + dijuij[min] (2)Fig. 1 Logistic technology „Hub-and-Spoke“and for the train s rg :t rgo= t + drgurg[min] (3)The “Hub-and-Spoke” technology can be combined with theline principle using the technology of multiple-section trains. Theschematic representation of this technology is in Fig. 1. Novak[21] and Vrenken [26] found that the network structure based onBlackout time during waiting for reload can be formularizedby 4:o o u ut = t - t + d -d -tlczrgijrgijir[min] (4)20 ● COMMUNICATIONS 3/2008
If we are unable to influence the last three timing logic elementsthat means that the travelling times of each train are dij u anddrg u and reloading time is l. Then we can lower the blackout timeby increasing the value of tij o to:ox ot = t + xijor by lowering t o rg value to:ox ot = t + x ; _ x 0irg[min] (5)Now we can extend the formula (1) to:ou out + x + d -t -x -d -tl0rgijrgrg[min] (6)Besides the boundary conditions like (7) there is also anotherone which ensures time locations of trains s ij . It may vary in fixedbounds (a ij , b ij ):a # t + x # bij ij ij ijSimilarly for trains s rg :a # t + x # brg rg rg rgRoutes L i and L r pass through the node u and two lines ofthose routes s ij and s rg are coordinated if there exist two numbersx ij and x rg , which fulfil conditions (8) and (9). So we can makea directed graph G (S, H), where (s ij , s rg ) ∈ H if node u existswe are able to coordinate those lines (S – set of routes, H – coordinatedgraph of transport network). The edges determine h ∈ Hwhich pairs of nodes can be coordinated but not all of the pairsfrom the set H can be coordinated simultaneously by a differentvalue of x ij . Therefore, a coordinated subgraph G(S, H) mustbe found where for all i 1, … n, j 1, … m i exist values x ij fulfillingthe condition (7).For the coordinated subgraph G there exist usually more possibilitiesfor the x ij value, which comply with each pair of nodes(x ij , x rg ) ∈ H conditions (7) and (8). The selection of final valuewill depend on the consignment volume f ir , which will be reloadedin a node from L i to L r . Here we establish a term optimal solutionfor coordinated pairs of trains. It is determined by the subgraphG:X = # x ij -; = 1,… ; = 1,…(7)(8)(9), (10)for i, j which comply with condition (8), for all (x ij , x rg ) ∈ H andcondition (7) and which minimize the value of the objective functionur :/ou ouur= f _ t + x + d -t -x -d -tliir_ sij,srgiijrg rg 1rgrgijrgijrg(11)If we expect that the values t o , d u , t are constant according tothe optimization task the value of objective function ur is minimizedafter fulfilling above mentioned conditions:ijijir $ijijir/ur= f _ x -xiir rg ij_ sij,srgi! Hl(12)The resultant form of objective function depends on subtractionof values x ij and x rg which are additional times to arrival ofa train on a train route t ij or departure of a train on a train routet rg . So if we want to set up the objective function for the train routemodel we have to come out from the formula (12) as described byCaprara [3] and Cerna [4].4.2 Formulation of a mathematical modelRailroad timetable set up is an intensive and long process. Thereason is in a limited use of a computer application. It is mainly aninteractive process between human experiences and automatedgeneration of timetable tools. Kryze [18] and Nielsen [20] suggestthat the whole travelling time for a consignment in intermodaltransport contains these components:● Travelling times between terminals,● Time spent at stops on the train route,● Waiting time (result of insufficient capacity of operation equipment),● Synchronization time (time needed to reload consignmentsbetween two trains).Shortening of first three times (travelling time, time spendand waiting time) is subjected to investments (of infrastructure).On the contrary, synchronization time is determined by timetableso that we are able to shorten the synchronization time only bychange of organizational set-up (non-investment character). Thereforeit would be better to work on optimization leading to minimizationof synchronization time, as described by Dirmeier [6].In railroad cargo transport there exist two types of synchronization:1. Waiting of train due to unloading of goods.During this first type of synchronization there is an extendedtravelling time for goods due to unloading, and therefore thereis no advantage from synchronized times.2. Waiting of goods for connecting trainIn the second form is extended travelling time of goods whichneeds synchronization.Reloading process (formation of synchronization time principle)of transport units between two trains is in Fig. 2. From thatfigure it follows that the waiting time has several significant spells.Those spells are due to shipping and traffic reasons. The mostimportant part is synchronization time which depends on a minimalreloading time. Waiting time is a result of insufficient capacity ofrailroad infrastructure or insufficient locomotives. This time maynot apply to each train. The size of that time is variable for differentgroups of trains. On the other hand, stopping time and timefor dispatch of a train must be kept to a minimum for each train.In Fig. 2, we can see a striking difference between the waiting timeof “not-reloaded” consignments in the first or second train and thewaiting of reloaded consignments between those trains. That canbe applied also for more than two trains in a station.COMMUNICATIONS 3/2008 ●21
Page 5 and 6: Mt = k$ Di(12) 4. Torsion moment at
Page 7: References[1] JOVANOVIC, R.: Tensio
Page 10 and 11: Fig. 3 Geometrical parameters of ch
Page 12 and 13: Fig. 13 10. eigenvector when the ei
Page 14 and 15: and D R _ y,wi=0 if y 0 (12) Dampe
Page 16 and 17: Fig. 22 Comfort for passengers for
Page 20 and 21: Fig. 2 Consignment reloading proces
Page 22 and 23: attached to individual tracks shown
Page 24 and 25: Juraj Gerlici - Tomas Lack *MODIFIE
Page 26 and 27: After the insertion of the previous
Page 28 and 29: where:k - is the basic spring stiff
Page 30 and 31: [2] GERLICI, J., LACK, T.: Methods
Page 32 and 33: Resulting from experience the degre
Page 34 and 35: Upon this strengthening of pretensi
Page 36 and 37: attained the 6th position of the be
Page 38 and 39: Jozef Jandacka - Stefan Papucik - V
Page 40 and 41: spacing of the fan from the measuri
Page 42 and 43: 5. ConclusionFrom the results prese
Page 44 and 45: REVIEWlines with numerous curves th
Page 46 and 47: REVIEWmeters from the point of view
Page 48 and 49: REVIEWBojan Cene - Aleksandar Rados
Page 50: REVIEWthe year 2006 in Slovenia sta
Page 53 and 54: REVIEWthat the GPS does not recogni
Page 55 and 56: REVIEWRadomir Brkic - Zivoslav Adam
Page 57 and 58: REVIEWfailures. For example, for an
Page 59 and 60: REVIEWJan Krmela *COMPUTATIONAL MOD
Page 61 and 62: REVIEWFor this reason tyres and whe
Page 63 and 64: REVIEWFig. 6 Computational model
Page 65 and 66: REVIEW- guarantee that the messages
Page 67 and 68: REVIEWIvana Olivkova *PASSENGER INF
Page 69 and 70:
REVIEWLike the other information sy
Page 71 and 72:
REVIEWFig. 1 Revolution of the poin
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REVIEWFig. 4 Transformation of the
Page 75 and 76:
BOOK REVIEWKavicka, A., Klima, V.,
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