My point was about elecrification costs rather than the viability or otherwise of a Calder Valley scheme. But it seems it gets a response cut and pasted to/from a totally different point.
As I suggested earlier that someone other than NR should manage a future electrification scheme, I should perhaps clarify that I agree with most of the above and the reason for my suggestion was that a private company that commits to a price then charges extra for scope changes might be a harder target for the politicians than NR which is effectively under DfT control. I do realise this throws up a whole host of other issues...
I'd also point out that the electrication clearances issue is, as far as we can tell, a foul-up somewhere in the UK in not accepting a network-wide derogation that was on offer. Therefore it can be reversed within the UK with or without Brexit.
And ALARP does appear to have been surpassed by ERIC in some quarters - the need to justify Eliminating the risk before you consider just Reducing it (and so on to Isolating and Controlling). The two should go hand in hand, if elimination wouldn't be ALARP then reduction is OK.
No, ALARP is a measure of where you stop within ERIC. Let me elaborate.
OLE at stations is a specific hazard. This risk that this hazard becomes a problem can be physically mitigated. The best way is to increase the distance between the OLE (and all other live parts such as pantographs, etc.) until the possibility of anyone being to reach disappears completely (Eliminate). Many stations have a road bridge over them. This bridge places an upper limit on wire height. Raising the wires to eliminate the risk may now require removal of the bridge. This will have a cost. In some cases this cost will be pretty astronomical and disproportionate to the risk.
We could raise the wires and the bridge as far as possible; less costly, but with higher residual risk. We will still have reduced the risk (raising the wires by any amount does this, mathematically) - Reduce - job done. However, the cost of these works (Fishergate at Preston, Trinity Way at Bolton) may still be significant when they achieve little.
In this situation, Isolation is deeply impractical (clearing the platforms before turning the OLE back on and the reverse) and would introduce other risks, control in this case is similar.
Where would you stop? Surely the question is, what is the magnitude of the risk?
There has been (IIRC) one passenger death and a few minor injuries caused by persons legitimately using a platform and coming into contact with live OLE, in about 45 years. Even allowing for a massively inflated (x 10) value of preventing a fatality, that's about £160m (ignoring the span of time it covers, too). I suggest that this would go nowhere near eliminating the risk, reducing the risk significantly or funding any kind of control or isolation. In conclusion, GL/RT1210 imposes controls that go massively beyond ALARP and thus artificially inflate the cost of electrification schemes. Yes, BritGov failed to renew its National Exemption, but that doesn't mean we should continue to punish ourselves!