Design software for overhead contact line systems

Project planning process

The following model scenario provides an overview of the project planning process.

First, the framework conditions that affect the design results have to be defined, such as the construction phases, the settings for the overhead contact line system that refer to the entire project, and the information on environmental influences.

The settings for the overhead contact line defined in the “Overhead contact line” tab (Figure 1) provide the basic properties for all newly created objects. They can be changed at a later time or specified by overwriting the properties of individual design

 

objects according to specific installation conditions.

The user is not restricted to the use of pre-defined value combinations determined by a specific model or design. All the values can be combined freely. Furthermore, there are several possible settings for the environmental conditions that have to be taken into consideration to prove the serviceability, in particular regarding wind drift, proof of spacing, or static calculations.

Contact line
Figure 1 - Contact line (click to enlarge)


After entering other project settings, the basic drawing file with the referenced basic data (e.g. the routing) can be inserted as a reference (Figure 2). This double-referencing of the basic drawings makes it possible to distort them, using different scales for each axis, without encountering difficulties at a later time.

The design process starts in the 2D mode with the layout plan. When designing an overhead contact line system, the primary goal is to place the contact wire in the best possible position for the current collector.

 

Therefore, the design starts with the clamping points of the contact wire. The properties of the clamps, which later constitute the connection to the head span systems (such as cantilevers and head span structures), are the basis for the support-specific properties. These properties include the height of the contact wire and the system, the utilization and design of auxiliary wires, and the lateral shift of the overhead contact line, among others. In addition to standard catenary lines, simple contact lines and overhead contact rails are available as well.

 

Environment
Figure 2 - Environment (click to enlarge)


After the subsequent “drawing of the contact wire,” it is brought into the required lateral position at the required height (“stringing”). Various functions, such as the distortion of the course of the contact wire, including the referenced track plan, as well as the

 

representation of the wind drift as a function of the selected project settings or the representation of a current collector profile that is suitable for the given project settings, help to obtain the required position of the contact wire quickly (Figure 3).

 

Stringing
Figure 3 - "Stringing" (click to enlarge)


Thanks to the 3D model of the contact line system, it is always possible to switch to the longitudinal profile in order to take the vertical profile of the head span structure, for example near bridges, into account. The representation can furthermore be distorted to optimize the position and provide proof of the spacing. To prove the minimum electrical spacing, boundary lines can be represented under certain environmental conditions, such as ice load or wear of the contact wire.

Following the preliminary definition of the mast positions, the clamps are then allocated to head span systems based on specifications and local conditions.

 

The systems can be single-track or multi-track cantilevers, head span structures, or portals.

Next, the mast-ups and masts are positioned in the terrain. The design tool makes it possible to connect each mast site or mast pair with a planned or surveyed cross-section. Based on the mast positioning, the mast length can be determined. The determined length is a property allocated to the object “Mast” and represented to scale in the cross-section. Any changes made in the cross-section are also adopted by the 2D layout plan.

 

3D view of a long-distance transport project
3D view of a long-distance transport project (click to enlarge)


Once the support points for the overhead contact lines and existing traction power lines, switches, switch connection lines and other equipment on the mast have been determined, the masts and mast-ups are selected by means of corresponding static calculations. Based on EN 50119 and the values for the environmental conditions entered as project properties, SIGNON OLAcad sums up all the forces, torques and momentums affecting the mast. The designer can see the total loads affecting the mast in the form of a diagram, comparing them to the durability of the mast.

For the planning of the construction phases, a

 

specific useful lifespan has to be defined for each

element in accordance with the construction phases of the project. This can be done in a single step for larger groups of various selected components. If several construction phases have to be planned and represented, the individual construction phases have to be selected successively as the active construction phase, and the design steps have to be repeated for each construction phase. According to the status of the construction phase selected as the current phase, the individual objects are represented in different colors as part of the existing system.

 

Traction line plan for a streetcar crossing
Traction line plan for a streetcar crossing