REGISTER

K.W. Whybird MIRSE

Queensland Railways

In association with the Main Line Elec-trifi cation Project, the Department's extensive private telecommunication network has been undergoing radical changes.

Existing open wire pole routes which, prior to elec-trification, formed the backbone of the communications network, are progressively being demolished and replaced with the latest optical fibre and microwave radio based Pulse Code Modulation (P.C.M. ) digital cornmunicatiorls systems.

Departmental operational requirements dictate that communications channels must be available at the foll.owing locations:-

(a) Major equipment rooms and microwave radio access points.
(b) Centralised Train Control (CTC) installations.
(c) Station Master's (SM) offices.
(d) Feeder Stations (PS).
(e) Track Sectioning Cabins (TSC).
(f) Autotransformer Installations (AT).
(g) Motorised Isolator Installations (NI).

The system chosen hacl to be capable of being immune to the overhead trac.tion .system as well as being able to economically access the above locations, which in practice, are distributed unevenly along the traclt with relatively close spacing. For example, on the Gladstone - Rockhampton - Blackwater and Branches section there are 4071tm of traclc with 77 required communication access points. This gives an average separation of 5.281rm between points.