Robotic Controlled Plant
We are producing significantly higher quality switch and crossing renewals – thanks to the innovative use of total station-controlled dozers. The dozers are used to excavate, lay and plane track ballast on modular switch and crossing renewal projects. With three dimensional (3D) laser control software installed, they are providing exceptional speed and accuracy benefits during excavation and reballasting activities, leading to significantly higher quality switch and crossing renewals.
The Problem
Up until 2008, we used conventional two dimensional (2D) laser control to guide plant excavating and laying the ballast formation and base stone layers on switches and crossings renewals. However, one of the major limitations of this methodology is that technical staff can only control vertical profile with manual adjustments for change of gradient, vertical curves and the application of cross-level and cant. These adjustments are complicated, time-consuming and prone to inaccuracies in excavation and base stone levels.
This poor control impacts on the ability to accurately align, plate-up, key-up and weld track panels. The efficiencies normally associated with a modular approach to replacement are, thus, significantly reduced.
The Solution
After investigating available technologies, we elected to develop the use of Trimble Total Station controlled bulldozers with 3D control. System and equipment testing was carried out with Korec (the UK distributors of Trimble surveying equipment).
Initial trials were undertaken at Manningtree where we teamed up with plant supplier Hydrex, who were very keen to perform the necessary modification to their dozers to support the control system.
The initial trials were successful and a second trial site was chosen, with the Total Station Control system being deployed at St Denys over four weekends. St Denys was a much more complex project than Manningtree, further testing the capability of the system. On this occasion, the dozers were supplied by Quattro, who – like Hydrex – were very ready to adopt the technology and modify their machines accordingly.
These trials were again extremely successful, convincing us to extend the development of this technology which in turn has created saving on manual correction and reduced the need for tamping requirements later.
Other benefits include:
- the design data is installed directly into the bulldozer, removing the risk of error
- a faster set-up, by removing the need for multiple lasers required in the 2D operation
- faster process, removing the need for constant checking and adjustments
- reduced rework, as the system delivers ‘right first time’
- removes the step errors, caused by ‘matching’ blade profiles across the width of a dig
- faster and more accurate excavation and reballasting
- much tighter control on ballast quantities
- greatly improved construction techniques, particularly on canted switches and crossings
- higher line opening speeds
- reduced number of tamping shifts
- increased life of the renewal.