The safety & control of running trains along the railways line is mainly based on Signalling & communications system.
The Signalling system of Sudan Railways Corporation (SRC) is very old, but still in work due to preventive maintenance although a number of difficulties have been observed . Sudan Railways Corporation is dealing with single line for running trains between each two adjacent stations (Block Section), hence the token instruments are used as far as the token system is simple and reliable for trains operation.
The existing backbone of telecommunications for S.R.C is open wires carried on the poles along the railways line between Atbara and Port Sudan. These wires connected all stations with dispatch traffic control in Atbara also token and block telephone between each two stations are connected through one copper wire running on the poles .
Anew Communication system has been introduced for S.R.C and they are including: –
High frequency radio ( SSB) system to communicate control offices through Five regions and central control office ( C.C.O ) in Atbara (H.Q)
Very high frequency radio system ( V.H.F ) to communicate form point to point ( Between stations) , locomotives and vehicles .
Private exchanges installed in five S.R.C regions for local and External telephone services through hot lines .
Also there are faxes – E-mail – Internet for administration officers and senior staff.
All stations between Khartoum – Atbara – Port Sudan are fully Signalling as defined in Sudan railways rule book – that is they are equipped with outer and inner home and starter signals on the main and the loop lines. Also there are distant signals stand for indicating the driver to minimize the speed for easy control.
In the main section (Khartoum – Port Sudan) is equipped with either double wire mechanical interlocking frames or with westing house lever frames, signals are operated by a single – wire and points by roding, and are lowered quadrant, distant signals are fixed and simple indicators and markers to train drivers as mentioned.
Running line points at crossing stations are operated from the lever frames, while siding points are operated by local levers, key released by keys that are normally locked in the frames, running line points are equipped with facing locks and lock bars.
Block control is by token instruments that operate over one wire carried on the overhead poles route. This wire also carries the station to station block telephone.
Anciently SRC has used signals light, with kerosene, and electric lamps fed by primary batteries controlled by photo – electric cells that automatically switch on the lamps at night. Now reflected tape is used to indicate the position of arm signal during nighttime.
All type of signalling used in Sudan railways are mechanical interlocking system. The electrical or electronics interlocking is not yet introduced .
The Existing Communication System:
Communications, facilities at the present time are installed along the railway lines for five regions consist of : –
* Selective call telephones system connecting a train controller (Dispatcher) to all station master for section Khartoum – Port Sudan. The main control office is located at Atbara HQ. Traffic department known as central control office (C.C.O)
* Block telephones between all stations are used to link stationmaster and to give line free.
HF radios installed at different important stations for continuous
VHF radios are installed in all Sudan railways crossing and main stations. Also radios are equipped in locomotives, further there are VHF walk talky radios for the shunting purposes and administration facilities.
The more effective system in main section is dispatch system central control office (C.C.O) depends on carrier system which is now using copper or reinforced copper wire carried on pole route from Khartoum – Port Sudan Known as over head route wires .
The overhead wires are subject to frequent faults, and long delays occur in affecting repairs now there is a plan to replace the old system by optical fiber cable buried along the line and owned by sudatel company.
Private exchange has been installed in Khartoum and Port Sudan for local telephone services. In Atbara there is 912 lines Small Digital Exchange, smaller ones in Kosti and Babanousa, some of them are connected through hot line from sudatel services.
Telephone lines consist of : -
* Local lines from sudatel company.
* Public telephone lines. Faxes for administration officers.
* Hot lines for PABX exchange and teleprinters.
Computer net works: -
Local area and wide area computer networks were installed in Khartoum – Atbara – Port Sudan.
This new system is playing vital part for railways communication especially for information and trains operation along the line.
Power supply: -
All crossing stations along the line are equipped with solar energy (Complete system).
* Connector and installation cable.
Others major stations are using commercial electric power supply which is 220 V 50 Hz connected with rectifiers and batteries.
Optical fiber and SDH equipment :-
Recently SRC has installed SDH equipment through optical fiber cable for all stations between Khartoum and Atbara HQ, this is replaced the old system of open wire in this section. The plan of the new system of SDH will contiune to connect all stations between Atbara and Portsudan section in nearly future.