Great Western Main Line electrification - ongoing discussion

[whole diary]

[Fourbee]

That sounds like a sensible incremental approach massively reducing the scope for things to go wrong.

[Bmblbzzz]

Is the objection to underfloor engines only to actual engines, presumably due to noise and vibration, or is it a preference for separate locomotives? I understood the point of having all wheels driven (electrically) was to increase traction and both reduce and better distribute weight, thus improving acceleration and reducing wear and tear on the track?

[ellendune]

That sounds like a sensible incremental approach massively reducing the scope for things to go wrong.

Yes far too sensible the politicians will never allow it!  Its too long term. 

[Rhydgaled]

Is the objection to underfloor engines only to actual engines, presumably due to noise and vibration, or is it a preference for separate locomotives? I understood the point of having all wheels driven (electrically) was to increase traction and both reduce and better distribute weight, thus improving acceleration and reducing wear and tear on the track?

Both, in my case, but the noise and vibration is the showstopper.

With most intercity trains, the benifits of units are less since most intercity trains need a top speed in excess of 110mph (which rules out UEGs^▸ (Unit End Gangway) and possibly needs a longer 'nose' which makes running units in multiple rather wasteful in terms of space, maybe not as much as a loco + DVT^‡(resolve) but with seated DVTs the gap will narrow significantly). Also, most intercity trains are on busy routes and need a decent number of coaches, which means the cost of a locomotive is balanced out by the cheaper unpowered coaches in a way it isn't on a shorter train. A good-looking locomotive (eg. class 91, class 43 (IC125 powercar)) can also add to the prestige value of an intercity train, particularly if fitted with cast nameplates with a sensible name.

Taken together, the attributes discussed in the above paragraph are not sufficient to rule out the use of EMUs^▸ (Electric Multiple Unit), they just make locomotive working a more attractive prospect than for other types of service. A decent intercity EMU (sadly I'm not sure we have one of those at present) is thus acceptable; an intercity DMU^▸ (Diesel Multiple Unit) is not (bi-modes are a grey area, if the diesel engines will only be running for a short time (Bristol to Weston-Super-Mare perhaps?) it probably is not too big a problem).

UEGs = Unit End Gangways

[broadgage]

Is the objection to underfloor engines only to actual engines, presumably due to noise and vibration, or is it a preference for separate locomotives? I understood the point of having all wheels driven (electrically) was to increase traction and both reduce and better distribute weight, thus improving acceleration and reducing wear and tear on the track?

In my case, the objection to underfloor engines is partly due to noise and vibration, but is also the fact that a short DMU^▸ (Diesel Multiple Unit), or even a pair of short DMUs coupled together simply do not feel like a proper intercity train.
A proper intercity train should be at least 10 coaches, and preferably 12 coaches, and be gangwayed throughout.
First class should be at one end, and preferably at the same end each day, with standard class at the other end and a buffet between the classes.
Seating should be mainly facing across full sized tables, with luggage space between the seat backs.

A pair of 5 car DMUs are a very poor substitute for a proper train, first class will be in two different and presumably random locations. And the first class host will be in other unit.

Haulage may be by diesel or electric locomotive as required. A locomotive or power car each end has a lot to be said for it. If the power cars are gangwayed to the rest of the train, then any spare space therein could be used for storage of luggage, cycles, and catering supplies.

EMUs^▸ (Electric Multiple Unit) are not as bad as DMUs, but for long distance or prestigious services I would still prefer an electric locomotive hauling an ample number of coaches, over an EMU. Several short EMUs coupled together and lacking gangways simply are not a proper intercity train.

[eightf48544]

The other advantage of locos and hauled coaches is that you can vary the set lengths for different journeys.

I believe that's how the Norwich service works (can't remember who works it now it's changed so often!) work long train sets from Norwich in the morning and back at night and shorter sets out of London in the morning.

[grahame]

The other advantage of locos and hauled coaches is that you can vary the set lengths for different journeys.

I believe that's how the Norwich service works (can't remember who works it now it's changed so often!) work long train sets from Norwich in the morning and back at night and shorter sets out of London in the morning.

With 5 and 9 car multiple units, that's the sort of thing that should be worked on the GWR^▸ (Great Western Railway) lines too.  Peak trains into London - 2 x 5 cars.  Shoulder trains 9 cars, off peak 5 (the off peak trains being at the "far end" of the line during the peaks.  Slight problem that in GWR land there are peak flows at some of the far ends too - like into Bristol.

You see similar on the regional commuter trains - there's a couple of "contra flow" trains in the morning peak out of Bristol that are just a single car to ensure the big trains are around the big flows.   Doesn't always work though - I know of one line where the pre-peak service in the morning and the post-peak service in the evening (and a lunchtime train) are 2 or 3 carriages, and the peak services are 1 carriage.

[stuving]

With 5 and 9 car multiple units, that's the sort of thing that should be worked on the GWR^▸ (Great Western Railway) lines too.  Peak trains into London - 2 x 5 cars.  Shoulder trains 9 cars, off peak 5 (the off peak trains being at the "far end" of the line during the peaks.  Slight problem that in GWR land there are peak flows at some of the far ends too - like into Bristol.

But once you allow for the non-passenger space in the end cars, a 9-car (627) is almost exactly twice the "length" of a 5-car (315). That is, I think, "by design" - it is (or was during IEP^▸ (Intercity Express Program / Project.) spec-writing) seen as OK to run long trains off-peak at low loadings, but not "sustainable" to do that with diesel (or semi-diesel) ones. Hence any bi-mode had to be a train of two halves.

[Adelante_CCT]

I know of one line where the pre-peak service in the morning and the post-peak service in the evening (and a lunchtime train) are 2 or 3 carriages, and the peak services are 1 carriage.

Hmmmm, i really can't think of what line Graham is talking about

 

[Rhydgaled]

The other advantage of locos and hauled coaches is that you can vary the set lengths for different journeys.

I believe that's how the Norwich service works (can't remember who works it now it's changed so often!) work long train sets from Norwich in the morning and back at night and shorter sets out of London in the morning.

With 5 and 9 car multiple units, that's the sort of thing that should be worked on the GWR^▸ (Great Western Railway) lines too.  Peak trains into London - 2 x 5 cars.  Shoulder trains 9 cars, off peak 5 (the off peak trains being at the "far end" of the line during the peaks.  Slight problem that in GWR land there are peak flows at some of the far ends too - like into Bristol.

The bit I've bolded is why* I think the fleet should haven been either all 9-car trains or a mix of 9-car and either 8-car or 7-car sets; the logic being that the peak flows at the "far end" are smaller than into London, so might manage with a 7-car set but not with a 5-car (I don't know the loadings, hence the 'might').

* not the sole reason, I also think that if all off-peak trains into London were only 5 coaches there might not be enough seats to go round, just because London is so big

But once you allow for the non-passenger space in the end cars, a 9-car (627) is almost exactly twice the "length" of a 5-car (315). That is, I think, "by design" - it is (or was during IEP^▸ (Intercity Express Program / Project.) spec-writing) seen as OK to run long trains off-peak at low loadings, but not "sustainable" to do that with diesel (or semi-diesel) ones. Hence any bi-mode had to be a train of two halves.

There was nothing saying all bi-modes had to be in two halves; although all the 9-car GW^▸ (Great Western) IEPs were ordered as 'electric' sets the ECML^▸ (East Coast Main Line) Aberdeen and Inverness routes were always intended to be a full-length bi-mode as far as I know; when the order was signed it definately already included 9-car bi-modes for the ECML.

Not sure where 'sustainable' comes in, I doubt sustainability factored very highly in the DfT^» (Department for Transport - about)'s planning; otherwise they wouldn't have replaced the IC225 fleet early and would have tried to plan for further electrification. If the half-capacity was indeed "by design" I think it more likely that the 'half-length' trains were designed as such so that a pair of half-sets could substitute for a full-length set if need be with no reduction in capacity.

[stuving]

There was nothing saying all bi-modes had to be in two halves; although all the 9-car GW^▸ (Great Western) IEPs^▸ (Intercity Express Program / Project.) were ordered as 'electric' sets the ECML^▸ (East Coast Main Line) Aberdeen and Inverness routes were always intended to be a full-length bi-mode as far as I know; when the order was signed it definately already included 9-car bi-modes for the ECML.

The order make-up never had to be made public before it was placed, though the requirement to offer 5-car and 9-car trains was in the requirement. I know less about the plans for the ECML, but I think the 9-car bimodes are meant for the Aberdeen and Inverness routes, which don't have much of a peak/off-peak difference. The equivalent routes on GWR^▸ (Great Western Railway) were left out of the IEP order, and there are 9-cars among the AT300s. The 5-car electric IEPs are, I think, for different routes rather than to be run as pairs - but no doubt that may have changed by the time they are in service. As you say there is that flexibility.

Not sure where 'sustainable' comes in, I doubt sustainability factored very highly in the DfT^» (Department for Transport - about)'s planning; otherwise they wouldn't have replaced the IC225 fleet early and would have tried to plan for further electrification. If the half-capacity was indeed "by design" I think it more likely that the 'half-length' trains were designed as such so that a pair of half-sets could substitute for a full-length set if need be with no reduction in capacity.

It was always intended for Mk IVs (not sure how many of them) to continue operating the faster trains (fewer stops) while the IEPs were seen as "semi-fast". And whatever you think about other parts of DfT policy, the choice of trains with the IEP order was just a straight choice - "how many trains of each kind to we want?". Buying new diesel (even if part-time) trains was seen as a potential source of criticism, so a few offsetting green brownie points were needed. Embodied carbon (or energy) doesn't feature much in the public's appreciation of greenness (nor DfT's I suspect), so minimising diesel burn was what they picked on. Subsequent history (i.e. air pollution issues) suggest that as PR^▸ (Public Relations) this may have been right.

Oh, and using bi-modes was indeed seen as favouring further electrification. For sections that would never be done before IEP, doing it later would now have some value, whereas with diesel-only trains it wouldn't. That's based on limited and unrealistic assumptions, obviously, but does have some internal logic.

A lot of this is in a DfT presentation dated 2011:

Great Western – by December 2017
• Electrification of all the busier and high speed sections – challenging, especially with planning issues
• Bimode for the low and medium speed route sections with lower frequencies
• Uses the capacity gains from the Reading scheme
• Takes Paddington to Reading up to ‘safe’ capacity limits
• Mix of 5 car, 8 car and 2 x 5 car workings with options to extend 8 car sets to 9 or 10 cars
• Greatly increased peak capacity with fast EMUs^▸ (Electric Multiple Unit) as extra ‘peak busters’ – in total 11,000 more peak period seats
• Reduced off peak waste by use of 5 car trains

East Coast – for December 2018
• Power Upgrade – London to Doncaster Auto Transformer
• Various capacity works:
• Joint Line
• Flyovers Hitchin and Shaftholme
• Peterborough capacity and possible grade separation
• Line speeds
• IEP trains primarily on semi fast services which enable MkIVs to operate faster fast trains to Leeds and Edinburgh
• Mix 5 car, 9 car and 2 x 5 car trains
• Use of IEP to Cambridge/ King’s Lynn and to N of Edinburgh
• 16 Min faster to Edinburgh and 3 trains per hour to Leeds and Newcastle

[Worcester_Passenger]

A lot of this is in a DfT^» (Department for Transport - about) presentation dated 2011.

Thanks for that link. I particularly like

Putting the ‘Inter City’ back in Great Western
• More trains serving more segregated markets
• Efficient resource utilisation
• Likely standard hourly pattern:
    • Swansea fast (non stop Reading to Newport)
    • Cardiff semi fast
    • 2 x Bristol fast (non stop to Parkway)
    • 2 x Bristol via Bath
    • Cheltenham
    • Worcester
• Bristol (Parkway and T.M.), Swansea, Cardiff, Worcester and Cheltenham all 15 – 22 min faster than today.

I look forward to the Worcester service being "15-22 min faster than today" [presumably 2011]. This will take us back to what we used to have back when the HSTs^▸ (High Speed Train) were first introduced.

[ChrisB]

Note Worcester not Hereford.

There's local comment that these new trains won't clear Ledbury tunnel

[IndustryInsider]

It does have a quite severe kink at the Malvern end of it, and is just about as narrow as a tunnel can be for a standard gauge railway.  I wonder what would happen to Hereford-London services if the IET^▸ (Intercity Express Train)'s aren't cleared for it?

[SandTEngineer]

I thought I read somewhere else that the IET^▸ (Intercity Express Train) had chamfered ends so that the coach profile is the same as a MK3?