Definition of the track

The train load (i.e. the group of loads) can move along a track of an arbitrary shape. The track may be a simple straight line track, a circular arc or a complex polygon with both straight and curved parts. When you define the track, you may use all the standard SCIA Engineer tools for the input of a polygon.

The procedure to define a new track

1. Open service Load.

2. Expand branch Traffic loads.

3. Start function Traffic lane.

4. Input the vertices of the track.

5. End the definition with [Esc].

Once a new track is defined, it is possible to set its parameters. The parameters appear in the Property window every time the track is selected.

Name	Defines the name of the track.
Use for calculation	The track for train load can be used also for the calculation of normal mobile load. If this option is ON, the track is used for the calculation of influence lines for moving unit load. If OFF, the track is ignored in that calculation.
Used nodes	(informative) Tells the number of track nodes (vertices).
Track nodes	Contains a list of all track nodes. Each end node of each track interval can be used to assign the slabs that are to be exposed to the effect of the train load.

Assigning a track to slabs in the model

In order to explain this action that may seem illogical at first sign, let us imagine a multi story storehouse with a track defined in the top floor. In general, a train of trucks (something like a train of airport trucks full of luggage) may be used to transfer the goods. And such a train can be operated in several floors of the storehouse. You then need to specify in which floor these trains operate and in which floor there are only offices.

In this operation you do not work with the track as a whole, but you need to assign the slabs to every interval of the track polygon (naturally, if the track has been defined as a single line or arc, there is just one interval to be assigned).

The procedure to assign a track to a slab

1. Select the track.

2. The property window displays a list of nodes (vertices) of the track.

3. Select the end node of the required track interval. (The end node of the interval is decisive in this operation).

4. Click the three dot button [...] corresponding to that node.

5. A small dialogue opens on the screen.

6. The left-hand side of the dialogue offers a list of existing slabs. The right-hand side of the dialogue contains a list of assigned slabs.

7. Select the required slabs in the left-hand side and move them to the right-hand side using the buttons between the two lists. NOTE: If the right-hand side list is empty, it means that the train load acts on ALL slabs.

8. Close the selection dialogue.

Important note: If the assignment of slabs to the track intervals is changed after the load cases were generated for that particular track, all the generated load cases (and also possible load case combinations made of those load cases) must be deleted and the load cases must be re-generated. Also the combinations must be defined again.