Wednesday, 13 July 2016

Napier Gisborne Line: Aerial Photos [3]

A big slip at Tunnel 6 is an ongoing issue in the Esk Valley. The hillside is slipping all around this area and has been doing so for many years.

The Mohaka Viaduct. The road is impeded where it passes under the viaduct due to the placement of one of the pylons.

Mangaturanga Viaduct just north of Raupunga.

Kopuawhara Viaduct.

In 2015 here is a new slip developing at 346.5 km between Tunnel 15 and 16.

During the construction of the line in February 1938 a major storm caused a flood at Kopuawhara Construction Camp which was washed away with the loss of 22 lives. The monument to this event still stands almost directly opposite the 347 km peg.

Washout at Tunnel 22 about the time the line closed.

Big Hut washout with extensive slipping in the hills around the areas. 2012 approx.

The hump in the track is the bypass of Tunnel 24 put through mid 1950s when the hillside was sliding so much that the tunnel collapsed under the pressure. In fact the hillside is still on the move here towards the sea as can be seen to the right.

Another trouble spot around 356.8 km where some material has slipped down onto the tracks in recent years.

South end of Beach loop where the washout occurred in 2012, with again evidence of more problems.

There's been a lot of trouble here at Wharekakaho Stream over the last four years.

Napier Gisborne Line: Some Aerial Photos [2]

Recent photo of the Waikokopu foreshore with protection works for the railway line.

The triangle at Wairoa. The Swifts meat works siding went off the end of it and was removed some years ago.

Ravensdown Fertiliser depot at Wairoa. It's not clear if this was replenished by rail in recent years of operating the line.

Wairoa River Bridge.

Nuhaka River Bridge. The wooden piers that were susceptible to teredo attack were replaced with concrete after the bridge collapse in 2005.

Centre (1950s extension) part of the Waipaoa River bridge. Due to severe flood scouring of the original and 1950s extension parts of the bridge in the 1988 Bola floods, the bridge has only been patched up due to the high cost of repairs not being economic. Trains are limited to 30 km/h and one locomotive at a time, and must stop running whenever certain levels of river flow or wind speed are reached.

Napier Gisborne Line: Some Aerial Photos [1]

As the debate continues to rage over the future of the Gisborne line, here are some aerial photos from the best quality that Land Information NZ or National Library has to offer.

Whites Aviation shot of Waikokopu. The station was at the far end of the big curve and the port must have still been somewhat usable at the time (1951) although once the railway was completed it became nearly superfluous. Note to the right the concrete blocks needed along the foreshore to protect the railway embankment.

Whites Aviation view of Opoutama in 1951, station  platform and shelter shed. Scoble (see reference list) seems to suggest the name was also used at Kopuawhara a little further up the line. This station seems to have been mainly for passenger use without a siding but small lots of goods may have been handled on an unattended basis until the 1980s. The closing date for passengers shown as 2002 must have been for specials.

Ravensdown Gisborne depot, one of a small number of sidings still operational in the area when the line closed.

Prime sawmill, another siding but the mill was closed some years earlier. A wood processing plant was to have been established on the cleared site to the left but work was stopped around 2008.
A washout at 348.9 km which must have happened since the line closed. If the description I received is correct then this location had old railway wagons as a retaining wall under the embankment which have collapsed into the river.
A new washout developing at Wharerata Walkway Station in this 2015 photo.
The area known as Blacks Beach around the Mahia Peninsula showing the erosion that is threatening the road and will affect the railway. The area above the track at this point is where the big slip came down in 1957 that closed the line for 2 months.

Thursday, 7 July 2016

Gisborne line fragile and damage prone

Well with a little help from some friends I was fortunate enough to obtain a copy of Chris Woods' out of print history of the railways in Eastland, "Steaming To The Sunrise", published 20 years ago. Now this book contains a lot of detail about the history of the construction and operation of the Gisborne Line. Here is a summary of key maintenance timelines as gleaned from it along with my other sources.

  • 1938, February: Major flooding on the incomplete line washes out culverts and embankments. Eskdale bridge completely collapses. Construction camp at Kopuawhara washed away with death of 22 workers.
  • 1938, May: Repairs to previous flood damage undone by further major flooding.
  • 1955, July: 100 metres of track pushed out of alignment by major slip at Waikokopu, causing closure for 10 days.
  • 1955, end: Line diverted at Tunnel 24 due to continual movement of hillside towards sea causing tunnel lining to crack. Tunnel eventually collapsed the following year.
  • 1956, December: Major slips at both ends of Mohaka tunnel. Repeat instances in subsequent years lead to portal extensions in early 1960s.
  • 1957, August: Huge landslide at Waikokopu closes 300 metres of track. Estimated 1 million tonnes of material slid downhill after prolonged rainfall. Reconstruction work takes three months in all, with line completely closed for the first four weeks.
  • 1977, June: Major rainfall and flooding causes severe damage to 27 km of track between Paritu and Muriwai. Repairs require the shifting of some 300,000 cubic metres of soil throughout the Whareratas. The line is reopened to limited freight traffic almost two months later, but repairs to a standard suitable for passenger traffic are not completed until early 1978.
  • 1983: Storm damage closes line for two months.
  • 1988: Cyclone Bola cuts railway in 69 places with slips and washouts. Napier-Wairoa section reopens after two months of repairs. 100 metres of embankment at the south end of the Waipaoa River Bridge is washed out requiring the bridge to be extended 145 metres in total. Although the line is finally reopened after 8 months of closure the passenger services are not reinstated. Several piers under the south end of the Waipaoa bridge are badly scoured by the flooding but to save on repair costs, only the former southern abutment is underpinned with new piles. The result is a bridge with a new permanent speed restriction of 30 km/h, an axle load restriction of 14 tonnes, a weight restriction banning more than one locomotive on the bridge at a time, and regulations requiring it to be completely closed whenever the wind speed or water level exceeds certain limits.
  • 2005, May: Nuhaka Bridge collapses while under repair due to teredo infestation of wooden piles. Installation of new concrete piers allows reopening of line after some two months. 
  • 2012, May: Major weather event causes three significant washouts in the Whareratas and the embankment is undercut by ponding at Wharekakaho Stream north of Beach Loop. Kiwirail estimates repairs at a cost of around $4 million. Decides to mothball Wairoa-Gisborne section of line. Napier-Wairoa remains open but is mothballed at the end of the year due to insufficient freight traffic.
  • 2015, June: Gisborne City Vintage Railway is given operating rights over Muriwai-Gisborne section subject to completing track repairs. Replacement of sleepers and rebuilding of several small bridges is eventually completed later in the year at a cost of more than $200,000 which has to be raised from grants and other external funding sources as the railway society has no money.
  • 2016, May: Gisborne District Council estimates a cost of around $45,000 to repair potholes at a level crossing on the section of line operated by GCVR. The railway society is unable to fund the work leaving the council to pay.
  • 2016, June: Further problems at Wharekakaho Stream near Beach Loop require a long reach excavator to be brought in to unblock the culvert under the railway line.
The above are the most major of the events that have happened on the line. We know that there have been additional other times when the line has been closed for periods due to slips happening and we also know that there has been a lot of damage to the railway formation alongside the Kopuawhara Stream where a lot of weatherproofing would be essential to address this damage in years to come. In addition there is another major issue along the line at Blacks Beach near Mahia, where erosion has cut into the ground below the highway which the railway is next to. Sooner or later this will result in the railway being undercut. The state of the Waipaoa Bridge is a major issue the next time there is a really big flood in the river, and the next flood control scheme for Gisborne appears to require the bridge to be raised higher which is likely to be an unaffordable expense for Kiwirail. The hillside at Beach Loop is constantly sliding towards the sea hence the work needed at Tunnel 24.