Petone - Relay Room

A selection of photos taken in the relay room of Petone Box. The photos were taken between 2007 and 2012.

I am not an expert on relays so any information on the various types of relays shown here would be appreciated.



The following are some of the companies who provided equipment at Petone:

  • Westinghouse Mckenzie Holland (Naenae)
  • Mckenzie and Holland (NZ) Ltd
  • Siemans and General Electric Railway Signal Company Ltd London.
  • General Railway Signal Co Ltd London
  • Westinghouse Brake and Signal Co London
  • ?? Telecommunications Ltd.
  • Electromagnetic ?? Ltd (EMR).


Relay room

The relay room is on the ground floor, entered by the blue end door. The panel is on the first floor.


Entrance to the relay room is via a work area, with a bench on the left.

Equipment rack

Racks supporting the various relays. The distribution frame is on the back wall.

Relays on rack

Each position on the shelf is labelled with the relay designation. The designation indicates the relay function. For example, 67RGPR is 67 red signal repeating relay and 66RLR is 66 signal reverse lock relay.

Cable hole

Wires to the panel on the first floor.

Photo to be taken.

The distribution frame.

Cable entry

The cable entry, with the distribution frame above.

Relay label

Relay 49903 was tested by Mr (or was it Miss?) M.R. a few weeks after the end of the Second World War.


Remnant (not operational) of a once extensive phone network at Petone.

Plug in relay

A way of using plug in relays in older installations.


A 60 second timer. Some of the timers have inspection stickers dating from the 1940s.

Another timer

Another 60 second timer. Inside the case are what look like Post Office relays.

Two coil relay

A neutral relay used as a track circuit repeater repeater.

Two coil relay

A neutral relay manufactured by the General Railway Signal Company, London.

Strange relay

A latching relay operated by a lever on the panel. Known as a "monkey on a stick" relay. Two vertical bars, connected to the Normal and Reverse coils respectively, move vertically. There are latches at the bottom. Used as a lock relay for points and signals.

Latching relay

The Normal coil of a "monkey on a stick" relay is latched (left). This relay is used in a signal circuit so the Reverse coil (right) does not have a latch, allowing the reverse relay to drop immediately the lever is put back to Stop. The Normal coil economiser contacts are bottom left.

Monkey replacement

A frame with two plugin relays functions as a Normal/Reverse lock relay, replacing a "monkey".

Track relay

A two-position two-element vane track relay. The relay is Up so the track is not occupied.

Two element vane relay.

A three-position two-element vane relay used in a points indicating circuit. This relay was tested on 1/1/1948. I wonder if they really did work on New Year's Day? Another relay of this type at Petone was made in April 1938.


A close up view of a three-position double-element points indicating relay. The points are Normal. Relay serial number 6026 was manufactured on 6/4/38. How many cards in a computer based interlocking will still be in use 74 years after installation?


A 10 micro Farad, 1500V capacitor.

Track feed transformer

A track feed tranformer out of use.

Newer style relays

Newer style plug in relays. The are used to provide functions added since the interlocking was installed - for example switch in/out and control of the Branch after the signalling was removed.


On the right a 110V AC to 12V DC rectifier. On the left an unknown device.

Last Updated: Tue Nov 6 08:12:50 NZDT 2012

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