Petone Signal Box

Petone was one of the few signal boxes remaining in the New Zealand network in 2013. Most other interlockings were operated by computer from train control. Opened in 1952, the Petone signalbox replaced a mechanical box dating from about 1905.

Petone Box had an individual function switch panel controlling a relay interlocking. The points and signals were operated by thumb switches on the first floor panel. By 1990 most of the track structures at Petone had been removed, leaving the Melling Branch and two crossovers.

In its final years Petone was switched in for just under thirteen hours per day, Monday to Friday, for Melling trains. It was also sometimes switched in at nights and on weekends to terminate trains during block of lines.

Petone Box was switched out for the final time at 1835 hours on Tuesday 24th December 2013. At 0600 on Thursday 26th December Petone Box ceased to be an operational site.

Signal cabin sketch

A 1948 sketch by the NZR Signals Branch of the proposed new signal cabin for Petone. It bears a resemblance to a "Hornby Dublo" signal box.

Petone Potted History

1874.  A single line railway from Wellington reached Petone. The alignment was to the west of the present track, approximately on the alignment of the Western Hutt Road (SH2).

1898.  Signals had been installed by 1898 as this Evening Post story about a large bush fire demonstrates. The Koro-koro bridge is that over the stream at the south end, opposite what is now Cornish St.

During yesterday the railway signals near the Koro- Koro bridge could not be seen for smoke, and trains had to be slowed down until they were clear of the smoke. (E. Post 13th Jan 1898).

1905.   The line from Lower Hutt to Petone was duplicated and moved to the east - onto the current alignment. A new station (the third), designed by Troup, was built. A signal box was built at the northern end of the up platform (date to be confirmed). (E Post 24 July P5 & 26 July P6 1905).

1940.  Western Hutt Road constructed west of the railway between the Petone and Normandale crossings. (E Post 11 Oct 1940 P4).

1952.  The present signal box was opened as part of the project to electrify the railway to Upper Hutt.

1958.  The Hutt Valley Junction to Lower Hutt section was singled and control of the Melling branch and Lower Hutt yard transferred to the Petone signal box.

1975.   Petone became a switch-out signal box.

1981.  Petone yard closed to all but private siding and motor vehicle traffic. Lower Hutt yard closed. (Rails Magazine June 1981).

1982.  Private siding traffic at Petone had ceased by this date.

1983.   Part of the Petone yard had been cleared and fenced by the end of 1983. (Rails Magazine December 1983).

1986. Off peak Melling services cancelled. Box switched in peak hours only.

Old Yard

(Above)   The site of the Petone yard is being converted to a commuter carpark (2007). The signal box windows have been painted to reduce the glasshouse effect.

2004 Off-peak Melling services reinstated, requiring the box to be switched in from 0615 to 1900 hours, Monday to Friday.

2009.  Switched in from 0445 - 2330. Evening and early morning trains replaced by buses Petone - Wellington for overhead upgrade. Also during second half of 2010.

2008 - 2010.  Regularly switched in at weekends for BOLs between Petone and Wellington. Part of WRRP (Wellington Regional Rail Project)

2013.   Invensys resignalled Petone. Petone Box was switched out for the final time on Tuesday 24th December 2013. At 0600 on Thursday 26th December 2013 Petone Box ceased to be an operational site.

I have created a pdf file documenting the re-signalling and closure of Petone Box.

Signalling & Interlocking 2010

Petone Diagram

Signals that Appear to Have No Function.  In 2010 very little remains of the once extensive interlocking at Petone. For example, 65 Down Advanced Starting and 73 Shunt from Up Main once protected cross-overs.

Branch Signalling.  All signals except 78 Down Directing from Branch have been removed from the branch. Track circuiting has also been removed. Indications on the diagram turn on and off depending on the order of occupancy of track circuits and the setting of 48 points.

Click on an image for More Information.....

Control Machine

The Control Machine.  In the 1950s personal computers were science fiction. The panel on the first floor is the equivalent of a GUI, controlling the relay logic on the ground floor.

Time element relay

The Relay Room.  View some interesting items of 1930s technology.

Petone building

The Building.  The Hornby Dublo style reinforced concrete building is one of only a few standalone signal boxes extant in 2010.

Pet 74

Petone Signals.   A photo gallery.


Blocking.   19th century technology is used in the 21st century to protect track workers and also vehicles that may not operate track circuits.


Replacing Indicator Bulbs.  The indicators on the panel diagram and on the desk use 12v ??ma bulbs. This page explains how they are changed when they fail.

Petone register

Timetable.  Trains signalled by the Petone signalman in 2007. I also make some observations about the timetable.

Part of 1975 train register

Paperwork.  Examples of paperwork including 1975 and 2009 train registers and train advices sent by telegram.

Branch indicators

Operating Irregularity.  From 1996 to 2013 the branch indicator lights could not be relied on. In addition, Melling - Wellington trains may have operated without authority.

Junction Priorities

Managing the Junction.   A variety of factors must be considered when deciding priorities at the junction.

Pulling in cable

New Interlocking.  During 2013 contractors installed a new interlocking at Petone.

Petone last days

Signal Box Closed.  Petone Box was switched out permanently on the 24th of December 2013. Study the final moments at the Box.

Petone aerial

"Aerial"   photographs of the Petone Station/Signal Box and yard site.

Petone History

Signalling History.  Diagrams explain the signalling layouts at Petone Station (excluding Hutt Valley Junction) from 1922 to the present day.

Interlocking in 1975

Interlocking in 1975.  Study the once extensive interlocking controlled from the Petone Signal Box.

control icon

Junction Interlocking Logic. I explain the logic behind the interlocking of Melling Junction. The Petone control tables for circa 1993 can be downloaded and I also explain how unusual running can lock points, requiring them to be hand wound.

Circuit Icon

Relay Circuits. I explain the relay circuits used to implement a 1930s era Individual Function Switch interlocking such as Petone, which was commissioned in 1952.

Petone emergency appliances

Miscellaneous.  Items that do not need a full page - or I am not motivated to create the page!

Petone Shunt Signals

Petone Shunt Signals

Control Tables

Study the Petone Control Tables for circa 1990.

Petone & Taita Compared

Although Petone and Taita signal boxes are of the same vintage and use the same technology, there is a significant difference in the interlockings, requiring different operating techniques at the two boxes.

Local Instructions

L824 (Cancelled by L71)

Petone L71 1975

L330 (Cancelled by L357)

Petone L357 2001

Petone September 2011

L357 refers to special Working Timetable instructions for working on the Branch. The 2009 version of these instructions can be viewed here. These special instructions would probably have been issued when signalling was removed from the Branch, sometime between 1983 and 1996 (an S&I is missing).

Petone Memorial plaque

ANZAC Memorial Flagstaff. An essay by Petone historian Gerald Davidson about the memorial flagpole outside Petone Station.

Last Updated: Friday 28th October 2016

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