Railway Survey Checking in n4ce
In the Designer edition of n4ce there are specialsit tools for processing surveys generated during rail surveys. These include checking overlapping points along rails, as you move your Total Station and generating parallel rails from Cant and Gauge measurments taken from a trolley.
A few manufactures have produced specialist equipment called trolleys for surveying railways. Rail-TQM is supplied by Railcare Advanced Instruments Limited www.rail-tqm.co.uk, GRP 500 by Amberg Technologies. See www.Leica-Geosystems.co.uk. Both systems have the ability to measure rail Gauge, Cant and Deviations, amongst others. n4ce has the ability to pick up geometry data collected by these trolleys. In the example being shown here The Gauge, Cant and Chainage have been recorded as Dimensions.
When carrying out rail surveys, special care should be taken to provide control and continuous checks on your survey data. Since there is a limit to the maximum sight distance from each station, as you move from one station to another it is advisable to mark the rail for say the last three measurements and re-record these positions from the next instrument setup creating an overlap of data.
In the example being shown below, this is exactly what the surveyor has done. After returning to the office and reducing the survey observations, checking the control readings, the next exercise is to compare the overlapping detail observations.
Here an element of pre-processing has taken place on the trolley with an export in GSI format containing survey observations and Dimensions for G=, C= and HC=.
|
When you select Rail Overlap you will be invited to select two overlapping rail strings. Once selected the adjacent Rail Overlap dialog box will appear. You will be expected to complete the entries as shown. Note the Tolerances on the right. |
|
|
|
The final part of the rail process is the generation of the parallel rail from the reference rail. Here we will use the recorded Cant and Gauge Dimensions. This normally comes from the Cant Stick, although it can be generated from the trolley. When you select the Railway Parallel option a second rail will be created from the Cant and Gauge. A report will give a summary of these calculations ? see printout below. |
|
