Digital Train Radio System Como Site Review of Environmental ...

3.1.4 Fibre Optics
A new fibre optic route will involve the installation of two new 12 core single-mode optical fibre
cables between the BTS cabinet and existing pit 2ATJ0472 at Chainage SW20+338 where the
fibres will be spliced to the existing RailCorp bearer network. The total length of the cable run
will be approximately 80 metres. The fibre optic route will run from the BTS cabinet via two
separate conduits in a single trench to an existing cable pit at Chainage SW20+286. The optical
fibre cables will then be routed underground via an existing pit and pipe route to existing pit
2ATJ0472.
3.1.5 Earthing
The earthing installation will comprise six earth stakes at a pre determined distance apart. The
grid will be nominally four by two metres, placing the six earth stakes two metres apart. Once
these earth stakes have been installed, the system will be tested and modified if needed.
The initial extent of the trenching for earthing grid will be around 20 metres. However, it can be
extended if the results show that the earthing arrangement is insufficient
3.2 Construction Methodology
The construction of the BTS site will require the use of approximately 300 square metres of land
within the eastern side of the rail corridor. This area will allow for the erection of the monopole
and the slab containing the BTS and power cabinets.
The monopole foundation will require an excavation approximately five metres deep with a
diameter of one metre. This will result in approximately four cubic metres of excavated material
which may include rock. The soil from excavations will be stockpiled before being used for
backfilling and/or disposed of site. Soil that cannot be used for backfilling, including rocks, will
be placed into a skip bin and removed from site at the completion of construction works. All
excavations will be covered during nights.
Installation of the earth grid, power and fibre optic cables will require excavation of trenches
approximately 1000 millimetres and 500 millimetres wide. The estimated length of all trenches is
200 metres. All trenching excavation will be backfilled before work finishes for the day. If this is
not practicable, trenches will be covered overnight.
The indicative construction methodology of the proposal will include elements outlined below.
• Non-destructive excavation before construction to establish underground installations.
• Site establishment.
• Excavation of the foundation for the monopole using excavator, drills or auger.
• Delivery and pouring of concrete on site for the monopole foundation.
• Installation of precast concrete slab brought to site for BTS and power cabinets.
• Excavation of trenches for power and fibre optic cables.