I was on the A99 between Wick and Keiss. The pipeline ran under the road, on rails. The map told me that these rails began - or ended - at the shoreline, with the landward end deep in the Caithness countryside, at a place called Hastigrow. And were dead straight.
The pipeline was mounted on little trucks that enabled it to run on this railway. Why?
The answer is that the pipeline is fabricated in welded sections inland at Hastigrow and, as sections are added, moves forward towards the shoreline, to be eventually floated out to sea and sunk onto the sea bed, becoming part of the oil or gas extraction network in the North Sea. I think this must be only at long intervals, as the rusty state of the rails suggests that the existing miles-long pipeline hasn't been moved for some time.
And yet the installations on the Keiss shoreline don't seem to have been mothballed, and the pipeline itself looks in good condition, ready to use. At the Hastigrow end - I had to go and see - it's quiet, but again not shut down.
I'm guessing that a team of engineers and security staff have to be kept on, to ensure that the pipeline doesn't deteriorate in the dire Caithness weather while awaiting the next step, flotation out to sea. Meanwhile the pipeline completely fills the available length of railway track, which is built absolutely straight to make it easy to tug the pipeline forward and out to sea.
What a strange thing to see, in this wilderness of rough grazing, heather and peat. When was it all first built? A plaque on the road bridge gave a clue, although it was somewhat hard to read.
Other puzzles: why there was a pair of silvery metal collars in the middle of each section of piping? And what was the purpose of the little huts that enclosed the pipeline at intervals - were they there to protect some critical weld from the elements, or to shelter welders doing some special job on the pipe? Who knows. There was nobody about to ask.
However, a little research on the Internet throws up these articles, which between them contain all you could possibly want to know about the operation at Keiss and Hastigrow. Too much information, even for the most curious of cats!
https://www.subsea7.com/content/dam/subsea7/documents/whatwedo/fabrication-yards/WickFabricationSite.pdf
https://www.caithnesschamber.com/News/archive/wester-gears-up-for-new-north-sea-contract
https://www.johnogroat-journal.co.uk/news/wester-launches-pipeline-in-record-time-129345/
https://www.johnogroat-journal.co.uk/news/subsea-7-order-hailed-as-very-good-news-for-caithness-134677/
https://www.wickharbour.co.uk/wp-content/uploads/2019/04/Equinor-Snorre-West-Bundle-Tow-Notification.pdf
https://www.railscot.co.uk/companies/S/Subsea_7_Fabrication_Yard/
Does this railway line - more accurately, these two parallel railway tracks - win the coveted 'Most Northerly Railway Line in the British Isles' award? No, it doesn't. The inland terminus at Hastigrow is slightly more northerly than Georgemas Junction, but not more northerly than the station at Thurso, which proudly retains its crown and contemptuously sees off this upstart.
