South Junction - Temporary Signalling

In 1968 the floors of the five 1886 vintage tunnels between Pukerua Bay and Paekakiriki were lowered to allow the passage of DA locomotives. However, even with the lowered floors the tunnels had insufficient clearance for 9ft 6 inch containers. In 1998 Tranz Rail further lowered the floor of the northern tunnel - number 7. It was expected that work on the other four tunnels would follow immediately but the work stopped.

On the weekend of 2/3 March 2002 the tunnel clearance work restarted. The NIMT was closed, freight trains diverted via the Wairarapa, the Northerner and Overlander terminated at Palmerston North and suburban EMUs terminated at Muri.

This page documents the temporary signal work that allowed the EMUs to reverse at South Junction without it being necessary to issue Mis 59 forms.

In December 2001 train 242 descends the 1 in 66 grade to Paekakiriki. Note the limited clearance in the tunnel.

Block Of Line

On the weekend of Saturday 2 March and Sunday 3 March the following work was undertaken between South Junction and Waikanae:

  • Tamping and Regulating
  • Traction Maintenance
  • Work in tunnels 3, 4 & 5.

"All Trains Stop" boards were erected between South Junction and the portal of tunnel 3. A sleeper was secured across the track at this point.

A similar Block of Line was also arranged for the following weekend - 9 amp; 10 March - to complete the work. Newspaper advertisements advised the public of the work.

Suburban Train Services

EMUs continued to run between Wellington and Muri with passengers being conveyed by bus betwen Pukerua Bay and Paraparumu. Over the period of the work approximately 75 EMUs reversed at South Junction.

A temporary low-speed light was fitted to 8RAB Up Departure signal and the signal re-designated as 8RABC Up Starting.

The advantages of these temporary changes are:

  • No need to manually lower the train stop
  • No need to check that 7 points are set and locked
  • No need to issue a Mis 59

Click here for a diagram showing the normal signalling arrangements.

Signal Classification

Signal Classes

The rule book defines three classes of signal and the rules under which each class may be passed at stop:

  • Stop & Proceed. The LE can pass this signal at stop provided the prescribed procedures are followed.
  • Stop & stay. The signalman can verbally authorise the passing of the signal at stop.
  • Departure. A Mis 59 must be issued for the signal to be passed at stop. A Departure signal authorises entry into a single-line block section.

Reclassifying A Signal

If the class of a signal or other item of infrastructure is changed the rules applying to it change. This can increase operating flexibility. Examples are:

  • South Junction A departure signal was temporarily classified as a Starting signal. Starting signals are stop & stay. This change meant that it was not necessary to issue a Mis 59 to each of the 75 or so EMUs that reversed here during the two day block of line.
  • Melling This single-line branch is now within Petone Station limits so the Petone signalman can verbally authorise trains onto the single-line.
  • Taranaki A section of mainline adjacent to a busy yard was reclassified so that shunting movements can enter the main line without the need to obtain a Track Warrant.

Low Speed Lights

What Is A Low-speed Light?

Low-speed lights display a short-range Yellow light when at "Proceed" but normally do not show any light. The lamps of Low-speed lights are backed by a triangular metal plate painted white with a yellow border.


Caution. Low speed

Red over Red over Yellow (short range light).

Points are in the proper position but track may be occupied or is suitable for low-speed only. Proceed at Low speed prepared to find track occupied, and ready to stop clear of any obstruction.

Mis 59 Forms

Where used. Mis 59 forms are used under both the Single Line Automatic Signalling Regulations (SLAS) and under the Centralised Traffic Control Regulations (CTC).

What They Are Used For. Entry to a single-line block section is authorised by a Departure signal. (Note: In SLAS territory timetable authority is also required). If a Departure signal fails Train Control may authorise the Locomotive Engineer to enter the block section by issuing a Mis 59 form.

Example. The form on the right is from the 1965 NZGR Rule Book. The 1988 version is similar although words have been changed to reflect changes in usage and procedures eg Locomotive Engineer instead of Driver and references to the Guard have been removed. The 1988 form also includes the warning that level crossing warning devices may not operate correctly.

8RABC Up Starting

8RAB Up Departure signal at South Junction has been temporarily re-designated as 8RABC Up Starting signal. A temporary low-speed light authorises an EMU to enter the single line section before reversing onto the Down Main.

The rule book states that a Departure signal may have a low-speed light or an Arrow Indicator for authorising other movements. I assume that "other movements" include entering a backshunt or siding. At this location the low-speed light authorises entry to the single line section so the signal has been redesignated as a Starting signal.

Note the train stop and the "wanted winker". I assume that the latter is no longer used now that trains are fitted with radio.

South Junction

This is South Junction. An EMU is about to cross from the Up Main to the single line, before reversing onto the Down Main on the right.

The rear of signal 8L Down Starting can be seen.

The run off siding is quite short and ends in a drop of about 54 metres to State Highway 1 and the adjacent Tasman sea. This is a rural and pleasant scene compared to the two lane Centennial Highway (SH1) below which is one of the more dangerous stretches of road in NZ.

The coastal scenery and the single line railway on a grade of 1 in 66 mean that SH1 at this point should be a popular stopping point. Unfortunately the state of the road and the volume of traffic mean that it is not safe to stop.


Click on either of the images for a set of 12 photographs recording a reversing movement on the single line at South Junction.

An Up EMU departs Muri to reverse on the single line. Signal 3132 is displaying yellow over red, indicating that the signal in advance, 8RABC Up Starting, is displaying Stop or Low-speed.

A down train enters Double Line Automatic Signalling Territory (DLAS) after reversing at South Junction. Muri Station is beyond the curve.

Signal 8RABC is out of sight on the right.

Last Updated: Friday, July 29, 2005

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