The New Zealand Railways Magazine, Volume 12, Issue 2 (May 1, 1937)
Electric Power Appliances in the Wellington Station and Yard
To most people the new station at Wellington appears a large and imposing building equipped with platforms by means of which people may reach the trains. Few people will realise that within the station building is installed a complete electric power supply and telephone equipment and in the station yard a complete interlocking system.
A description of the various phases of this equipment will be of interest and may start with a consideration of the power supply as the whole station depends upon this for its operation.
The electric power supply for the Wellington yard, taken from the Wellington City Council at 11,000 volts, is brought into a main power house (see illustration) and from there distributed at 11,000 volts to the main building, locomotive sheds and goods sheds. This distribution is carried out by means of a ring main so that should a failure of the cables occur an alternative supply can be given to these buildings.
Another of our illustrations shows the substation (in the station building) from which the power is supplied to the various services in this building. The 11,000 volts supply is here transformed to 400/230 volts and distributed by means of. 400 volt ironclad switchgear and armoured cables to subboards situated throughout the building.
In addition to the ring main supply previously described, the 11,000 volts supply is transformed to 3,300 volts in the main power house for the purpose of feeding the signalling installation throughout the yard, to Upper Hutt on one line and Tawa Flat on the other. As it is essential for safe operation of traffic that this supply shall not be subject to failure in any possible way, a standby plant driven by a petrol engine is installed in the power house so that in the contingency of the Council's supply failing, this plant can be brought into use at a few minutes' notice and keep the safety appliances working.
The main supply from the City Council is also supplied by means of a ring main so that if a failure occurs on one side of the supply power can still be maintained through the other.
The electrical equipment in the station building includes electric lighting, cooking and Refreshment Branch requirements, driving calculating machines for the Chief Accountant's Branch, some radiators for heating, and driving the motors for circulating hot water for the heating system. Other services include the automatic telephone exchange and lifts, of which there are four for passengers, one for goods and three service lifts.
There are over 50 motors used in the building, varying in size from a fraction of a horse power up to 10 horse power capacity, the total installed load under this heading, including radiators, being 1,200 horse power.
Electric clocks have been installed in all offices, in the various public rooms of the building and on the platforms. These clocks are electrically driven from a master clock situated in the telephone exchange and provision is made that should power fail, the accuracy of the clocks is maintained. The dials of the two outdoor clocks (one facing Featherston and the other Bunny Street) are internally illuminated. The lighting is controlled by an electric eye which automatically switches on the dial lights when daylight fails.
In the automatic telephone exchange, arrangements are made whereby any person requiring the Railways Department in Wellington dials the number 47-800. The calls end on a manual board at which five operators are seated. Immediately a call is received, an operator answers and connects the call through to the person or office wanted. Calls from the offices outwards are made direct to the Post and Telegraph Department's exchange. In addition to public calls dialled from the various offices, it is arranged that each office may call any other office in the building, or through the operator on the manual board can be connected via the Railway trunk lines to any station in the North Island.
(Our illustrations show the manual board and the automatic exchange).
As an adjunct to the telephone exchange, provision is made for what is known as a watchman's service. A watchman going the rounds of the offices must, from 30 different positions, dial a certain number. This number goes through the automatic exchange and records on a chart the time and the office from which the call is made. A fire alarm service is also provided whereby from numerous locations in the building a fire alarm number may be dialled, which call automatically connects up with the Wellington City Council Fire Brigade. Each group of offices is equipped with call bells and indicators to suit the various requirements.
Loud speakers will be located on the platforms and in different rooms of the station building and by this means passengers will be given information concerning the departure and arrival of trains. It will also be possible to provide broadcast music in waiting and dining rooms and to advertise activities of the Department as necessary.
The District Traffic Manager's office, situated on the first floor of the main building, controls the running of trains in the Wellington area and in these offices is installed the train control system. From the control room the movement of all trains between Wellington and Marton and Wellington and Napier is guided by telephonic reports and plotted on train running charts by the Train Control Officer.page 30 page 31
This officer arranges the various train crossings and supervises the running of trains so as to avoid delays to traffic. The equipment in this office consists of a selecting device whereby the officer can select any station at will. A loud speaker enables any station in the district to speak to the Control Officer without the necessity for that officer using a telephone receiver.
It is intended as a further development of the communication services to install teleprinters in this office. These instruments are really electric typewriters which are installed at each end of a telephone line. Letters typed on a machine in Wellington will be reproduced as letters on the machines at other stations. The first installation of these instruments will work between Wellington, Wanganui and Auckland.
The new Wellington yard is about two miles in extent and, with the exception of a few signals and points in the goods yards, is wholly controlled from one main signal cabin. It will be appreciated that to control a yard of this length and size from one main cabin involves a very complicated electrical system in order to ensure that trains pass safely through their respective routes and only to lines which are clear. The signalling is operated by electric power and it has already been mentioned that every care is taken to ensure that the power supply shall be entirely reliable under all conditions.
The main signal cabin, where the electric interlocking machine consisting of 127 levers is installed, is situated about a-quarter of a mile north of the station building in close proximity to the main substation. The signals are those known as the three-position, colour-light type and give the well-known red, yellow and green indications to drivers. The points are operated by motors which are connected to the relative levers in the interlocking machine.
Situated above the interlocking machine is an illuminated diagram whereon the positions of trains in the various parts of the yard are indicated by lights. The signalman is thus aware at all times what parts of the yard are occupied and where trains are moving, There are approximately 80 indicating lights installed in this diagram and the signalman can work quite safely with this and does not require to see the actual trains themselves. Behind each of the levers are small indicating lamps which tell the signalman whether the lever is free to be pulled and whether the mechanism which it controls has responded to the movement of the lever.
The interlocking between signals and points is effected electrically and it is only after all the necessary conditions are complied with to ensure the safe passage of a train that the indicating light behind the lever will show free and indicate that the lever can be pulled. Unless this light shows, the lever is locked and cannot be moved from its normal position.
Trains moving through the yard put the signals to “Danger” behind them independently of the signalman and it is impossible for the signalman to allow a train to proceed on to a section of line which is already occupied.
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It has been mentioned that the points are operated by electric motors. There are 70 of these machines in the yard and the points are moved by them in approximately three seconds. While a train is passing through a pair of points the power to the motor is cut page 32 off, thus ensuring that the points cannot be moved under a train.
What is known as electric detection is employed as an additional safeguard, the sequence of conditions when a train is signalled being, firstly, that the road must be clear, secondly, that all the points must be in the correct position and, thirdly, that the signalman pulls the correct lever.
Should any of the conditions not have been complied with, it is not possible for the lever to be pulled and, further, if any of the points are at all out of adjustment then the signal will not go to clear as the electric power to operate it passes through contacts on the particular pair of points over which it applies. An inside view of the signal cabin showing the interlocking machine and levers is the subject of one of our illustrations. In this the illuminated diagram can be clearly seen, as can also the indicating lights behind the levers.