I E P why do we need it?

[whole diary]

[IndustryInsider]

I wonder how on earth we've managed up until the second decade of the 21st century.

I don't think we've managed particularly well.  Just look at the complete and utter chaos when the wires are (frequently) down, or the power supply is switched off on the East Coast or West Coast routes.  I'm reminded of a situation at Crewe I found myself in a a few months ago when an empty engine derailed south of the station, but my train (and another Pendolino) in the station were unable to move northwards due to that section of current being isolated.  

As more and more of the network is electrified, more and more trains are likely to be affected by these things (countered by the general better reliability of electric trains over their diesel counterparts), so to me it makes sense to provide an alternative means of getting round a power outage, such as the one described above, and if that's not possible then at least the train can generate suitable conditions on the train until the line is cleared.  Perhaps longer term those engines can be removed and replaced with batteries when the technology is mature and cost effective enough?

[stuving]

As more and more of the network is electrified, more and more trains are likely to be affected by these things (countered by the general better reliability of electric trains over their diesel counterparts), so to me it makes sense to provide an alternative means of getting round a power outage, such as the one described above, and if that's not possible then at least the train can generate suitable conditions on the train until the line is cleared.  Perhaps longer term those engines can be removed and replaced with batteries when the technology is mature and cost effective enough?

Remember that the IEP^▸ (Intercity Express Program / Project. This will offer more capacity on routes, save money, give a consistent and safe service and meet customer requirements. Intended to replace HSTs.) process didn't tell the bidders how to provide either limited movement for electric trains nor off-wire services, though it did define some of the options (like defining a locomotive as not supplying train power). Bidders were to decide between loco-hauled electric trains and bi-modes, and work out what supplies the alternative power whether routine or back-up. And, I guess, they can replace them during the contract with an alternative that does the same job better if they want to (though not without DfT^» (Department for Transport - about)'s say-so).

Having just found (again) a DfT presentation that says that, it occurs to me that the need for on-board power on loco-hauled EMUs^▸ (Electric Multiple Unit) may have disappeared. Hitachi's bid offer bi-modes, not loco-hauling, as the solution for off-wire routes. So the on-board diesels now only have one mandatory use: limited movement. Of course there is nothing to stop the supplier providing more than the mandatory minimum.

[stebbo]

This is really exciting stuff - so many railway services start from a big city (let's call it "London") with a lotta services each hour, and electric is obvious.  But the along the way, the lines branch, some services terminate and the remaining services reduce in frequency.

OK - but, for example, I live in Gloucestershire and use the Cotswold Line; I used to live in Hereford. For the Oxford to Worcester/Hereford stretch, batteries aren't much use and a DMU^▸ (Diesel Multiple Unit) (effectively) lugging electric traction equipment - and vice versa - around doesn't seem that sensible. Same if you live beyond Bristol, say around Plymouth or Penzance (and I'm sure the diesel engines will welcome hauling the electrical equipment up the South Devon banks).

For emergency use doesn't a small diesel unit in a driving unit seem a useful idea; otherwise have an electric locomotive on one end and switch it to a diesel when required as on ECML^▸ (East Coast Main Line).

[grahame]

OK - but, for example, I live in Gloucestershire and use the Cotswold Line; I used to live in Hereford. For the Oxford to Worcester/Hereford stretch, batteries aren't much use ...

I'm not suggesting it's an "everywhere" answer. But it might provide for ... Paignton when via Newton Abbot is electrified, for trains calling at Frome when electrification goes to Taunton, for extending current Thames Valley suburban trains from where the electrification runs out to where the current suburban service ends (and that may include Hanborough and perhaps extras to Moreton in Marsh). Looking in your neck of the woods again, for trains into Worcester when Bristol - Birmingham is electrified.

[stebbo]

I agree - but how long before we see the wires going to Plymouth or Penzance? Or further down the Berks & Hants line? And electrification of the Cross Country route from Bristol to Bromsgrove won't help (if that gets done anytime soon).