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COLORLIGHT SIGNALS
Controlled or semi-automatic colour-light signals are controlled from a Lever frame, control panel or console and are used on double as well as single line sections. Every controlled or semiautomatic colour-light signal has a distinctive number which is preceded by a code letter.
Automatic color-light signals are used in the section between stations and are not controlled from a signal cabin and are normally at " proceed " when the section of line controlling the signal is unoccupied. Every automatic color-Light signal has a distinctive number which is preceded by the letter " S " and is provided with an illuminated letter " A " fixed below the signal aspect.
When a signal cabin is switched out, an illuminated letter " A " is displayed below the aspects of semi-automatic signals for the through running Iines and the signals are placed under automatic control.
Controlled or semi-automatic colour-light signals are of the two-aspect, three-aspect or the four-aspect type.
Automatic color-light signals are of the three-aspect type. Color-light signals are fixed to overhead structures or to posts or brackets or close to ground level alongside the track. Three-aspect signals are used for main line working at stations or on the section between stations and mean
Red light.
Danger-stop.
Yellow Light. Proceed with
caution-be ready to stop at next signal and/ or to negotiate points beyond next signal at
restricted speed.
Green light.
Proceed--next
signal at " Proceed " or " Caution ".
CONTROLLED OR SEMI-AUTOMATIC TWO-ASPECT SIGNALS.
Two-aspect signals are used for controlling train movements. The aspect displayed is red or yellow or green; repeating the " proceed " aspect of the main signal when on account of curvature of the line or other cause, that signal cannot be seen for the required distance.
Yellow light. Proceed with caution-main signal at " caution ".
Green light. Proceed-main signal at " proceed ".
No aspect shown. Driver may proceed cautiously towards the main signal and must be ready to stop, if necessary, within the distance he can see ahead.
FOUR ASPECT SIGNALS
In special cases, when a signal is at " danger ", and it is necessary to give a driver warning thereof two consecutive signals in the rear, a fourth aspect is used in conjunction with a three-aspect signal. In this case an additional yellow aspect is used and is fixed below the three-aspect signal,
The additional yellow aspect is displayed only in conjunction with the yellow aspect exhibited by the main signal and means
Two yellow lights. .... Proceed with caution-be ready to pass next signal at restricted speed.
A fourth aspect may also be used in conjunction with a main colour-light signal as a goods or siding signal, the " proceed " aspect must be displayed before a driver departs from a station or interloop on a single line where token working is in operation, and in addition he must be in possession of the correct token for the section over which he is about to travel.
Automatic Colour-Light Signals.
An automatic color-light signal is placed at " danger " by the leading locomotive or vehicle of a train as it passes that signal. When an automatic signal is placed at " danger " by the passage of a train, the signal will remain at " danger " until the train, complete, has passed clear of the portion of line controlling that signal, where after the signal will return to the normal position.
ROUTE INDICATORS USED IN CONJUNCTION WITH SIGNALS
Route indicators are used in conjunction with signals where there are facing points giving access to different Iines. The route indicator shows the route set up, or the platform road into which the train is being admitted. This route indication is given by means of illuminated number{s) or letter[s), or a combination of both, or an illuminated direction arm.
Route Indicators in Conjunction with main signals; the route indicator may be fixed above or below or alongside the main signal to which it relates
The route indication is displayed only when the signal to which it relates, IS at " proceed
POSITION LIGHT SHUNT SIGNALS
Position light shunt signals are used where necessary in conjunction with color light signals. They may be of the one position or two position types.
A one-position shunt signal is fixed below a main color light signal and displays only the Caution position by means of two white lights at an angle of 45 degrees.
A Two-position light shunt signal may be fixed near ground level or on a post by itself. The danger position is indicated by means of two white lights in the horizontal position, and two white lights at an angle of 45 degrees in the caution position.