59CosG95
Established Member
All of the above is quite correct.Again, Napsbury will only be a sectioning site for OLE isolation purposes (like most of the MML locations where switchgear is visible). In normal operation the Midland Main Line is only fed at Borehamwood and Chalton (Grahame Park still has its 132kV DNO connection as a backup, I assume).
My understanding is that KO1a modification works on the original "BedPan"* stretch are split into three distinct groups - resectioning (which includes a northward shift of the neutral section between the Borehamwood / Chalton feeds), conversion of feeding system (replacing return conductors / booster transformers with return screening conductors / aerial earth wires means reduced power transmission losses) and mechanical OLE mods (regrading of fast line OLE and registration arm adjustments). It's the third group that'll remove the 100mph limit on electric rolling stock south of Bedford.
[* Whoever came up with that way back when must have had quite the dry sense of humour]
Additionally, the "OLE Cubed" programme is replacing structures at risk of failure; STCs with STCs, and headspans with portals. These are mainly at the southern and northern ends.