''The Diamond Line'' and High Voltage Cable Link

By Peter Dunne

 

During the 70s and 80s I was a British Rail Cable Jointer's Mate whose duties included maintaining the High Voltage Cable Link (33,000 Volts) from Fawkham Junction Substation, on the Main Line, to Northfleet Grid, now adjacent to Sainsbury's. Apart from the occasional natural cable breakdown, there were also some foolhardy people whose idea of getting rich quick would be to unearth the buried cable, for the most part in concrete troughing. We never actually found any bodies, but on one occasion found a hacksaw part way through the outer sheathing; they or he were so lucky! We also witnessed the last train which ran to the coal depot at Southfleet Station, which must have been in 1976. My boss at the time had been on the railway since the 1930s and he always referred to it as ''The Diamond Line'', it being the preferred route of Diamond Merchants fleeing the Nazis from Amsterdam, en route to Holborn Viaduct for Hatton Garden.

 

The route of the High Voltage Cable ran from the National Grid site, which is still adjacent to the A2 and Hall Road, in a south westerly direction, obviously following the old track bed across the now demolished A2 steel overbridge on raised metalwork about knee high, still in concrete troughing, but covered in cement for added security. So the cable only ran roughly half the length of the actual line, and had no actual purpose for the line itself as of course it was not electrified. This was a vital link to Fawkham Junction to feed local Southern Railway Substations, which then converted the 33,000 volts down to 650 or 750 volts DC for the 3rd rail voltage. These substations are normally spaced at roughly 3 mile intervals along the track.

 

I would add that working on that particular line compared to the rest of the larger patch was a pleasurable experience, just like a walk in the countryside without the hassle of avoiding high speed trains coming at you!