Surveying services for the SBB

Switch pre-measuring for renewal (1st and 2nd tamping process)
Switch-Control refers to switch reconstruction and essentially consists of calibrating the new switch while the existing switch is still in operation. The marking protocol corresponds to the AWG (switch recording geometry) protocol, with the difference that the calibrated fixed points are (inevitably) located on objects outside the switch to be replaced, e.g. on neighbouring tracks, engineering structures, etc.

Preparation

• According to the information provided by SBB’s project manager (surveying of the switch by the SBB), the projected location of the new switch (external securing points) is marked.
• Inclusion and marking of switch connections (own marking points in the track axis)
• Defining and marking the sections for the 1st and 2nd tamping process while observing the permissible levelling ramps
• Creating the corresponding AWG protocol

Switch conversion

• Separating the switch to be removed at the AWG-marked and labelled points
• Installation and calibration of the new switch or switch parts, according to the secured and marked points (AWG protocol)
• Position correction with the Universal Tamping Machine: loading the AWG protocol, alignment and tamping the new switch. Absolute correction with reference to the AWG fixed points (with the PALAS measuring system)
• Final measurement (e.g. with the MEPHISTO track measuring device)

Works for the 3rd tamping process

• Follow-up check of the position of the new switch and final determination of the area of the 3rd tamping
• Positioning the fixed points in the track axis
• Creating an AWG protocol for the 3rd tamping process
• Position correction with the universal tamping machine: loading of AWG-protocol, alignment and tamping of the new switch. Absolute correction with reference to the AWG fixed points (with the PALAS measuring system)
• Re-measurement at control points (e.g. with the MEPHISTO track measuring device)

For the renewal, a 3D terrain model for the subgrade, the formation protection layer (FPL, if available), and the pre-graveling is created based on the routing data from Toporail. The DTM (Digital Terrain Model) module from Leica is used together with the corresponding tacheometre from Leica. The tacheometre is used on the construction site to check the progress of work (excavation, introduction of new material) in relation to this 3D terrain model. This ensures that the calculated volumes are maintained as precisely as possible and that the construction site can proceed as planned.

Surveying took place during ongoing train operation.

150 switch renewals per year