Title
Customisation of Leica GeoMoS Software - Real Time Automated
Deformation Monitoring System in the Rail Environment - North
Strathfield Rail Underpass Project
Abstract
Introduction:
The North Strathfield Rail Underpass Project (NSRU) is part of the Northern Sydney
Freight Corridor (NSFC) Program, a joint Australian and NSW Government initiative
to improve capacity and reliability of freight trains between Sydney and
Newcastle. The NSRU project involves construction of a rail underpass at North
Strathfield including tunnelling beneath existing operational commuter and
freight railway lines, installation of new and upgraded track, civil works and
platform upgrades and a new aerial concourse at Concord West Station.
To ensure that tunnelling operations do not impact upon the integrity of existing
track infrastructure, a need was identified to design and implement a 24 hour a
day, 7 days per week automated real time monitoring system (ADMS). This was
also required to operate within existing client maintenance specifications.
Project requirements:
The project monitoring system must measure and alarm on the following 4 key rail
variables
- Long twist, measured over a baseline length of 14m at 2m stations
- Short twist, measured over a 4m baseline length at 2 m stations
- Top, change in elevation measured over a 4m baseline length at 2m stations
- Line, deviation of the track in plan over a baseline length of 8m at 2m stations
In addition to this, any output must display the various readings against its
relevant alarming criteria and also provide a graphical display of those results.
All of these 4 key rail variables must be measured across the entire zone of
influence of the proposed tunnel measuring some 200m in length and involving
the use of over 450 monitoring prisms.
Problem statement:
- There exists no “off the shelf” solution for an application such as this given the
unique project requirements
- At any one time there will be an unknown number of trains passing through the
site and affecting the height of the rail when under load.
- No permanent fixtures were permitted to be attached to the existing sleepers
upon which the rail is fixed.
- Construction machinery will be operational around the boundary of the
monitoring area that may affect line of sight to prisms and backsights.
Solution:
There are three main facets to the solution of this problem, those being:
- The Management Component: This includes the breakdown of the monitoring
area into manageable zones, linked to construction activities, the determination of
suitable survey control and the proper use of the base lining period for error
minimisation etc.
- The Hardware component: this includes the theodolites, prisms, stanchions,
power source, communications etc.
- The Software component: This includes the software platform to control the
theodolites measurement sequence, a way of automating a usable output and a
system of alarming based upon that output.
Leica GeoMoS software was identified as being the platform that included the
functionality, most similar to that required by the project having the ability to
autonomously control the Hardware components and the ability to measure
deviations in level and longitudinal/transverse to user defined alignments.
The Microsoft SQL database, which underpins GeoMoS, has the ability to be
queried, its data output, used as a basis for calculation and alarmed through the
use of third party software packages resulting in an output fit for purpose.
Result/Conclusion:
The NSRU automated monitoring system has proven capable of determining
deformations in the 1-2mm realm and has produced an automated output
suitable for use in determining track deformation to client expectations.
Acknowledgements:
This project would not have been possible without the tireless work of the
following individuals.
Mr Neil Ashcroft – Engineering Segment Manager, GSR Asia, Leica Geosystems
Mr Richard Ingham –NSW Survey Manager, C.R.Kennedy & Company
Thanks also to NSRU Alliance and Transport for NSW for the opportunity to
present this paper.