SIGNALLING, INTERLOCKING and the TABLET SYSTEM at the FIRST PAEROA RAILWAY STATION

Ohinemuri Regional History Journal 48, September 2004

By J A T Terry

When the line opened to Paeroa on 20 December 1895, there were no fixed signals, all signals being given by hand or flag during daylight hours and by hand lamp during the hours of darkness. All points were hand operated and those for the main loop line were padlocked.

The opening of the branch line to Waihi saw a need for fixed signals to cover the Junction points south of the bridge over the Ohinemuri River where the line joined the main line from Frankton. Commencing with the first train on Thursday, 9 November 1905, fixed home signals outside the Junction points were brought into use. The signal post had two arms, the top arm applying to trains approaching from the direction of Frankton, the lower arm for trains approaching from Waihi. On 4 December, a home signal was provided at the north end of the station for trains approaching from Thames. The signals were operated from a three-lever frame at the south (Waihi) end of the station building.

For the Junction points, the following instruction was inserted in the Working Timetable:

Trains running on or too or from Waihi Branch must not foul points at the Junction siding (near Paeroa) until points have been unlocked by Guard, who, after a train has passed through, must see that points are locked for the Main Line.

It sometimes happened that there was no line clear at the station for a train to berth and it was necessary for the train to stand outside the home signal. If the line was not completely clear, the train could be brought forward under a green flag moved slowly up and down. However, the signal was 613 yards from the station and the driver not being in view of the station, the officer with the flag was required to move forward until he could be seen by the driver. To overcome this, a raised platform was provided so that the driver had a better view of the flag officer, but this was not a success. The District Traffic Manager at Auckland suggested a "calling on" signal be provided. This was a small semaphore arm placed on the signal post, below the home signal. When lowered, it indicated to the driver that the line ahead was not completely clear, but he could pass the home signal at danger and the train could be brought forward into the station as far as the line was clear. The District Engineer was not in agreement and in July 1907 arrangements were made to shift the Junction points closer to the bridge. This allowed the home signal post to be moved forward five chains and drivers, when halted at the signal, could clearly see a flag signal from the station.

Between April and August 1907 the tablet system was brought into use between Paeroa and Waihi. For this a tablet machine (for Karangahake) was installed in the station office.

From 1900 there had been a policy of making some of the larger station yards safer by the provision of starting as well as home signals and the interlocking of all fixed signals with the main line and loop points worked from a signal box. At 6 00am on Monday, 23 September 1912, these arrangements were brought into use in Paeroa. There was a signal box with forty-seven levers (six were spare to allow for future expansion if necessary) and a ground frame box with ten levers. The main box was elevated and sited on the eastern side of the Waihi dock road, ninety-three yards south of the station platform. The ground frame was just south of the Puke Road crossing at the eastern side of the line to Thames. Distant signals were provided for trains approaching from Waihi, Frankton and Thames. There were also starting signals and discs mounted on gantries for shunting movements. At the centre of the station the scissors crossing was protected by directing signals.

To lower the distant signals would have required a strong pull of the lever by the signalman. The Thames distant was 1074 yards from the signal box, the Frankton distant, 1066 yards and the one from Waihi, 970 yards. The Junction points were twelve yards south of the bridge and instead of the Main and Branch homes being on the same post, separate posts were provided. All points on the main and loop line were operated from either the signal box or the ground frame. At night, apart from the three distant signals, which, because of their distance from the station were kerosene lit, all signals and discs, as well as the signal box and ground frame, were gas lit, gas being supplied by Ohinemuri Light and Gas Power Coy. Following the closure of the Gas Company on 31 January 1925, it was necessary to light all the facilities previously lit by gas, with kerosene.

Two signalmen were appointed to work the box which was open daily, except Sundays, from 5 30am to 8 30pm. The ground frame was under the control of the signal box and operated by shunters.

In December 1914, when the tablet system was extended from Morrinsville to Paeroa, tablet machines were provided for Mangaiti on the main line and Komata and Hikutaia on the Thames line. They were probably placed in the station building alongside the Karangahake machine, rather than in the signal box. In May 1925 another machine was added for the Tirohia Service Siding.

On 31 August 1925, the new station was opened. While the old one no longer catered for the general public, certain railway functions required the retention of the signal box and ground frame. The most important of these was the control of the Junction points and signals protecting the single line over the bridge and on to the new station. The tablet machines for Karangahake, Mangaiti and the Service siding were placed in the signal box. The machine for Hikutaia went to the new station office and that for Komata withdrawn as it was no longer a tablet station. There was a new tablet section between the signal box and the new station, tablets for this section being inscribed "Paeroa - New Station". A tablet machine was placed in the box for the new station. On 4 March 1926, the north back shunt at the old station was removed and with it the signals and points involved. Construction of the double track from the station and the new double track bridge over the Ohinemuri was progressing well. On 19 April 1926 the line to Frankton over the new bridge was brought into use. The original bridge would be used solely for Waihi trains until the Waihi portion of the new bridge was brought into use on 14 June 1926.

With two lines now in use into the new station, the Junction points on the south of the old bridge were no longer required and there was thus no further need for the signal box and the ground frame. After 5 00pm on Sunday 18 April 1926, they were closed and demolished. All remaining signals and points were removed. The tablet machines, except the one for Paeroa New Station which was now redundant, were transferred to the new station office.

The two signalmen were given other duties. Mr W E Ouston was placed at Puriri as tablet porter and Mr A Bain placed at the New Station as a porter.

So ended the original Paeroa Station.

I have not located a photograph of either the signal box or ground frame and if any reader can help, I would be grateful.

GLOSSARY

Distant Signal: The first signal faced by a driver when approaching a station. It had a fish-tail notch on the arm.
Home Signal: The next signal faced by a driver.
Directing Signal: Used only in station yards for the purpose of directing trains to various platforms.
Tablet System: By the issue of a token (tablet) to the driver, it ensured that no more than one train would be on a section at the same time.
Interlocking: A system by which a signalman could not set conflicting train movements.
Working Timetable: A private document ‘for the guidance and exclusive use of members of the Department’. It contained instructions on running trains, etc.

REFERENCES

District Engineer NZR Hamilton files: 204/3 Paeroa Signalling. 26/104 Bridge No 25 Paeroa.

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PLAN OF SIGNALLING

Signalling and Interlocking Circular No 144 for Paeroa Junction.

It shows the position of signals and points worked from the signal box and the ground frame. The measurements at the top indicate the distance of the signal arms from the ground level.

The train on the Ohinemuri bridge is heading for Waihi. In front of the engine can be seen the post which will hold the Advance Starting signals. They will indicate to the driver which line the signal refers, the top arm the main line and the bottom, the branch. In the distant left, the home signal post, the signals guarding the Junction points, top arm main, and bottom, branch. These will disappear when the new signals are in use on 23 September 1912. Note the wires attached to the bridge. There are eight in all, sox for the new signals and two for the present home signals. These latter two will be removed when the new signals are in use. (Auckland Weekly News, 12 September 1912)

Looking south showing the directing signals protecting the scissors crossing at the centre of the station. In the distance, almost level with the edge of the verandah, are the starting signals for the main (top arm) and the loop or sidings (bottom arm). (S C Smith photo, postcard - Author’s collection.)

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