Joseph_Locke
Established Member
Since I've been told off for using an existing thread, I'll start a new one.
1. This would be true, but bridges have interminable lifespans (120 years) so rarely come up for reconstruction at the right time (vide Lever Street on Manchester-Preston). Secondly, unless there is an active electrification plan, the Civils Asset Manager will never get funding to speculatively raise a bridge (unless it was cheaper to do it that way). Speculative wiring would only really be advantageous of each end of the new wire joined two places up (which might involve rebuilding, track lowering, etc. way beyond the bridge in question.
2. Some things are mandatory (when present):
3. This depends on what performance you're wanting to buy. Current bi-modes are OK-ish EMUs with diesel donkey engines, good only for the smallest of gaps and useless on any kind of hill. If you went for a class 220 with a pantograph car added then perhaps this might perform better. Any change to and from OLE is best done stationary (to avoid embarrassment) so perhaps the IPEMU concept might be a better bet, as it doesn't involve starting diesel engines.
This characteristically elegant summary raises three things which, as an interested layman I would like to hear more of:
1. Cost attribution: I fully accept that if this were done for the sake of electrification it would kill it dead, but if demolition and rebuilding needs doing anyway, would it be appropriate to make put those horrific costs "against" electrification? Could this be turned on its head to something like "We've got to rebuild the bridge, with all the pain that entails, why don't we use the opportunity to wire under it while we're at it?"
2. "Electrification costs": it seems to me that three things happen when a section of line is electrified:
is it appropriate to include all of 2 and 3 under electrification, shouldn't some or much of them happen anyway?
- it is electrified
- the route is improved (tracks renewed, curves eased, speeds raised and the like)
- signalling is modernised
3. Intermittent electrification (or intermittent wiring): Raising bridges and lowering tracks costs a fortune, causes a lot of disruption and takes ages. With bi-modes now built and planned need we do so many engineering alterations?
Informed responses welcome.
1. This would be true, but bridges have interminable lifespans (120 years) so rarely come up for reconstruction at the right time (vide Lever Street on Manchester-Preston). Secondly, unless there is an active electrification plan, the Civils Asset Manager will never get funding to speculatively raise a bridge (unless it was cheaper to do it that way). Speculative wiring would only really be advantageous of each end of the new wire joined two places up (which might involve rebuilding, track lowering, etc. way beyond the bridge in question.
2. Some things are mandatory (when present):
- Providing vertical headroom for the OLE
- Finding somewhere to put the switchgear, feeders, etc.
- Providing the OLE
- Immunising the signalling system against 25kV induced voltages
- Protecting the signalling maintainer from the OLE (these last two sometimes trigger a resignalling of the line)
- Gauge clearing the route for the new electric rolling stock (generally fixing issues with platforms)
- Upgrading the earthing arrangements for station furniture, CIS, etc. and for fences and pipelines in the vicinity
- Raising parapets to comply with GL/RT1210
3. This depends on what performance you're wanting to buy. Current bi-modes are OK-ish EMUs with diesel donkey engines, good only for the smallest of gaps and useless on any kind of hill. If you went for a class 220 with a pantograph car added then perhaps this might perform better. Any change to and from OLE is best done stationary (to avoid embarrassment) so perhaps the IPEMU concept might be a better bet, as it doesn't involve starting diesel engines.