Arrival signals In Track Warrant Territory 

Arrival signals are replacing facing points indicators at loops in Track Warrant Control (TWC) territory. These signals are equipped with A-Lights.

Indications are as follows:

• A   Red over Red Reflector with both subsidiary lights blacked out - Stop, points not locked or train approaching other end
• B   Yellow over Red Reflector with "A" Light - Proceed on Main Line. Points locked Normal and tracks clear to far end of Station. The A-Light is redundant. This is consistant with Double Line Automatic where a top unit may show yellow or green with the A-Light illuminated.
• C   Red over Red Reflector with "A" Light and "L" light - Proceed onto Loop. Facing points locked Reverse. Loop track may be occupied. LE must have Track Warrant or permission from Train Control. The signal is Stop & Proceed but it is not necessary to wait the regulation 10 seconds.
• D   Red over Red Reflector with "A" Light only. Proceed at low speed. Points Locked Normal. Track may be occupied. LE must have Track Warrant or permission from Train Control. Signal is Stop & Proceed but it is not necessary to wait the regulation 10 seconds.

Reason For Configuration Of Arrival signal

I was puzzled about the use of the A-Light on TWC Arrival signals until I realised that the key to understanding is the way the points are operated. Then it all fell into place and the arrangement seems to be consistant with New Zealand signalling practice.

In SLA areas the points are hand operated and cannot move unexpectedly under a train. Therefore the Arrival signal can be Stop & Proceed. In TWC areas the points are motor operated so the Arrival signal must be Stop & Stay. A means must therefore be provided to indicate to the LE that the points are set and locked and will not move under his train (for those occasions when the signal is passed at Stop in accordance with the regulations). That is the purpose of the A-Light. It serves the same function as in Double Line Automatic signalling.

Alternative Configuration Using Arrow Indicators

The Rule Book defines Arrow indicators and as an "armchair" expert I believe that a simpler arrangement would involve horizontal and vertical arrows. My proposal would also eliminate the inconsistancy that the "10 second" rule when passing Stop & Proceed signals at Stop does not apply in TWC areas. See the diagram opposite.

Indications are as follows:

• A   Red over Red Reflector with both subsidiary lights blacked out - Stop. Points not locked or train approaching other end.
• B   Yellow over Red Reflector - Proceed on Main Line. Points locked Normal and track clear to far end of Station.
• C   Red over Red Reflector with Right (or Left) Arrow - Proceed at Low Speed onto Loop. Facing points locked Reverse. Loop may be occupied. Track Warrant or permission from Train Control required.
• D   Red over Red Reflector with Up Arrow - Proceed at Low Speed on Main. Points Locked Normal. Track may be occupied.Track Warrant or permission from Train Control required.

Extract from 1988 Rule 54 (b): When an Arrow Indicator exhibits a White arrow light in the facing direction or a related Colour-light in the trailing direction, the interlocked points are locked in the correct position and all movements over them must be controlled by a hand signal from the shunter.

A Track Warrant or permission from Train Control would replace the hand signal.

68 Down Starting From Down Main (Woburn) is fitted with an A-Light. When illuminated it indicates that the station is switched out and the signal is a Stop & Proceed. The A-Light detects the points.   (45-20)

Automatic Stop & Stay signal 1237 on the Down Main just south of Ava protects the switchlock controlled Fletcher Siding. Normally the A-Light is illuminated, converting the signal to Stop & Proceed. When the switchlock door is opened the signal goes to Stop and the A-Light goes out, converting the signal to Stop & Stay.   (36-21)

A-Light Controlled By Track Circuit

At Taita, Porirua and Plimmerton in the Wellington suburban area push buttons are provided to allow an Up train to reverse when the station is switched out. These three stations are equipped with A-Lights.

When the track circuit in advance of the Up Home signal is occupied the A-Light on the Home signal goes out. This prevents a closely following train entering the section under Stop and Proceed rules before the reversing button is pressed.

Detecting points

Double Line Automatic Regulation 3 (1988) includes the following paragraph:

Where there are points in the section ahead of a Stop and Proceed Signal which has been passed at "Stop" the Locomotive Engineer before the train passes over the points, must examine them and see that they are so secured that the train may pass safely over them.

In the Auckland and Wellington suburban areas the A-Lights detect the points. An A-Light illuminated indicates that the points are correctly set and locked and so the Locomotive Engineer need not examine them when passing the signal at Stop.

2. Train Stopped at Stop and Stay Signal

(a) Stop and Stay Signal Equipped with an "A" Light - If detained detained at a Stop and Stay signal equipped with an "A" light, and the "A" light is not illuminated, the Locomotive Engineer after ascertaining that the signal box is switched Out (or, in the case of a switch-locked siding, that the switch lock is locked), and upon observing that the line is clear, must cautiously move the train forward to the next signal. Where there are points in the section ahead of the signal the Locomotive Engineer must examine the points to see they are correctly set and secure so that the train may pass safely over them.

(b) Intermediate Stop and Stay Signal - If a train is detained at an Intermediate Stop and Stay signal which is not equipped with an "A" light the Locomotive Engineer (or a member of the train crew so instructed by the Locomotive Engineer) must communicate with Train Control from the adjacent telephone. Train Control, after being satisfied that the section ahead is not occupied, may authorise the train to pass the signal at "Stop".

If an Intermediate Stop and Stay signal has been passed at "Stop" Train Control after being satisfied that the section ahead is not occupied may authorise the train to proceed.

Note-In connection with the passing of these signals Locomotive Engineers must ensure that the train proceeds cautiously, being prepared to find the section obstructed or displaced rail or points wrongly set and must not assume that any obstruction is protected. Level crossing in the section equipped with automatic warning devices must, also be aproached with caution as the alarms may not operate correctly. If the signal next in advance is observed to be at "Caution" or "Clear" the Locomotive Engineer must not relax vigilance but must until he reaches the signal be prepared to stop the train clear of any obstruction.

3. Train Stopped at an Intermediate Stop and Proceed Signal

(a) When a Locomotive Engineer observes a Stop and Proceed signal at "Stop" he must stop the train; if, at the expiration of 10 seconds, the signal is still at "Stop" the train may proceed cautiously past the signal, the Locomotive Engineer being prepared to find the section occupied or Obstructed, points wrongly set, or a broken or displaced rail.

Where there are points in the section ahead of a Stop and Proceed Signal which has been passed at "Stop" the Locomotive Engineer before the train passes over the points, must examine them and see that they are so secured that the train may pass safely over them.

(b) After passing a Stop and Proceed signal at "Stop" the Locomotive Engineer must not assume that any obstruction in the section is protected, but must regulate the speed of the train so that it can be stopped within the distance he can see ahead and clear of any obstruction.

Note-In connection with the passing of these signals Locomotive Engineers must ensure that the train proceeds cautiously, being prepared to find the section obstructed or a displaced rail or points wrongly set and must not assume that any obstruction is protected. Level crossings in the section equipped with automatic warning devices must also be approached with caution as the alarms may not operate correctly. If the signal next in advance is observed to be at "Caution" or "Clear" the Locomotive Engineer must not relax vigilance but must, until he reaches the signal, be prepared to stop the train clear of any obstructions.

(c) If, after passing a Stop and Proceed signal at "Stop", a Locomotive Engineer becomes aware that there is a train stopped in the section he must stop his train and except when verbally instructed or handsignalled by a responsible member of the crew of the train in front to draw cautiously forward, must wait until the train has proceeded on its journey before again starting his train. If, however, the train is observed to be moving through the section the second train may follow it at a safe interval.

Note-In view of the possibility of a train which has passed a Stop and Proceed signal at "Stop" being in the same section as another train, strict attention to and observance of tail lamps after dark, or when visibility is bad, is of the utmost importance.