Great Western Main Line electrification - ongoing discussion

[whole diary]

[Noggin]

"The first Super Express Trains will enter into passenger service in Summer 2017, and will bring more frequent services, reduced journey times, and more seats once electrification of the line is complete."

Summer 2017? Where?

Edit - I've just noted that the Hendy Update report p88 states  "Bi-mode IEP^▸ (Intercity Express Program / Project.) trains will be introduced in Summer 2017".  But question still stands.

AFAIK^▸ (as far as I know), this first batch (class 800, class 801) are intended to replace the HSTs^▸ (High Speed Train) on everything but long-distance services to Devon and Cornwall via Newbury, which will be given over to the 802's, which have been procured separately and have a slightly different spec.

However, the 80x's potentially need some gauge clearance work to be complete before they can be introduced, so they might be limited to certain services at first, perhaps Cardiff services?

[Gordon the Blue Engine]

So they'll be on diesel (so 100 mph max) the whole way initially, which will extend journey times.  Difficult PR^▸ (Public Relations) exercise - "here are the new trains, but it's now 10 minutes longer to London".

edit .... but I suppose the alternative is that they sit in the sidings doing nothing.

[paul7575]

However, the 80x's potentially need some gauge clearance work to be complete before they can be introduced, so they might be limited to certain services at first, perhaps Cardiff services?

I'm getting the impression this isn't as significant a problem as first mooted.   They seem to cope with the North London Line OK on the way to North Pole, (so far), and there's not been any news of them hitting platforms all the way up and down the ECML^▸ (East Coast Main Line) either.

Could it be that the design has met the existing infrastructure, rather than the other way around?

Paul

[stuving]

So they'll be on diesel (so 100 mph max) the whole way initially, which will extend journey times.  Difficult PR^▸ (Public Relations) exercise - "here are the new trains, but it's now 10 minutes longer to London".

edit .... but I suppose the alternative is that they sit in the sidings doing nothing.

... but ...
for "all the way" read "just the part of the route where the speed limit is over 100 mi/hr and an HST^▸ (High Speed Train) could have wound itself up to above that",
we know that (officially) they are allowed to go faster if their little engines can come up with enough horses for the gradient,
the power:mass ratio of an 800 is slightly higher (7 vs 6.2 by my reckoning - kW/t including all auxiliaries),
the DMU^▸ (Diesel Multiple Unit) has far better adhesion so can use its power from lower speed.

Note that in this quote:

"The first Super Express Trains will enter into passenger service in Summer 2017, and will bring more frequent services, reduced journey times, and more seats once electrification of the line is complete."

the new timetable and all its goodies are not promised until after "electrification is complete". So any use until that change will be on individual services.

I'd imagined that during the first year (800s due May 2017 to Feb 2018) priority would be to get the HST refurb/cascade for Scotrail underway, by reducing fleet size, so something like:
1. replace HSTs pretending to be big turbos on peak services
2. replace a few power cars so unreliable they need scrapping (if any).
3. replace any other HST services with more stops than most.

It will be interesting to see if they runs in ones or twos during this period, won't it?

[ChrisB]

My understanding is that the first services will be replacing HSTs^▸ (High Speed Train) on the North Cotswolds. Those HStTs allocated to Scotrail are on a tight deadline with no opportunity for delay.

[Stroud Valleys]

that would tie in with the long dwell times on the existing timetable, plus not many 125 mph areas for this route. That line and the golden valley would make sense as the first delivery of services to release some trains for the scots

[Rhydgaled]

So they'll be on diesel (so 100 mph max) the whole way initially, which will extend journey times.

Summer 2017 is some time away yet, there will be some sections electrified by then, so they probably won't be on diesel 'all the way'. Alot of the way maybe. Also I think there have been claims that the pre-series 800s have reached 125mph on diesel on the ECML^▸ (East Coast Main Line) during tests, and there's apparently no rule saying a lower linespeed applies if they're running on diesel. Thus it is just a question of whether they have enough power to reach 125mph on diesel on an adverse gradient, downhill they'd get to 125mph eventually. As most of the 125mph sections of the GWML^▸ (Great Western Main Line) are relatively level the journey times probably won't be much slower, particularly if enough wires are up by then.

I'm getting the impression this isn't as significant a problem as first mooted.   They seem to cope with the North London Line OK on the way to North Pole, (so far), and there's not been any news of them hitting platforms all the way up and down the ECML either.

Could it be that the design has met the existing infrastructure, rather than the other way around?

Or it could be that only a small amount of work was required to clear them on those routes and Network Rail has already done it. As for platforms on the ECML, have the 800s gone as far as York yet? As far as I know all/most ECML stations south of York aren't sharply curved, and the 800s are probably no wider than existing stock so on straight track there should be few if any issues.

My understanding is that the first services will be replacing HSTs^▸ (High Speed Train) on the North Cotswolds. Those HStTs allocated to Scotrail are on a tight deadline with no opportunity for delay.

Interesting question of where the first 800s will be used. As well ScotRail wanting their IC125s, it is said elsewhere on this forum that Gand Central are taking on the current 5 Great Western class 180s from 2017, so perhaps the first route will be the Cotswolds line as you suggest but with the 180s going first followed by IC125s when sufficient 800s are available. Just a guess.

[ChrisB]

No "when...available" as I understand it - those Scots IC125s are going on a set date.

[IndustryInsider]

My understanding is that the first services will be replacing HSTs^▸ (High Speed Train) on the North Cotswolds. Those HStTs allocated to Scotrail are on a tight deadline with no opportunity for delay.

Interesting question of where the first 800s will be used. As well ScotRail wanting their IC125s, it is said elsewhere on this forum that Gand Central are taking on the current 5 Great Western class 180s from 2017, so perhaps the first route will be the Cotswolds line as you suggest but with the 180s going first followed by IC125s when sufficient 800s are available. Just a guess.

The North Cotswold Line, and indeed Paddington-Oxford's that are HSTs (which are increasing from May) are indeed the obvious first services to be 800s, replacing the 180s and HSTs will at least get a small number of them into service on a route that won't be impacted at all journey time wise.

[Gordon the Blue Engine]

I accept the point about journey times not being adversely affected if Class 800^s replace HST^▸ (High Speed Train)^s on North Cotswold.  Realtime Trains shows that the major point to point timings on this route for HST^s and Turbos are within a minute or two, so Class 800^s should be OK.

I presume that Class 800 acceleration on diesel is better than Turbos but worse than HST^s.  As a bonus their automatic doors may help dwell times compared to HST^s (assuming, of course, that the door closing process is quicker than Voyagers).   

[IndustryInsider]

I presume that Class 800 acceleration on diesel is better than Turbos but worse than HST^▸ (High Speed Train)^s.  As a bonus their automatic doors may help dwell times compared to HST^s (assuming, of course, that the door closing process is quicker than Voyagers).   

There will be a big difference in dwell times - even if the rather pedestrian doors of a Voyager are fitted. 

Acceleration wise, on diesel I'd imagine that they will be better than HSTs in the lower ranges (up to 40mph) and comparable from then until the higher ranges (90+ mph) where they'll start to struggle.  So, not as good as a 180, but not too far off them and absolutely fine (probably better than a Turbo/HST) on routes with fairly frequent stops and a 100mph top speed like the North Cotswold Line.  After all, they've been specified to run on diesel on the route beyond Oxford for the foreseeable future.

[stuving]

Acceleration wise, on diesel I'd imagine that they will be better than HSTs^▸ (High Speed Train) in the lower ranges (up to 40mph) and comparable from then until the higher ranges (90+ mph) where they'll start to struggle.  So, not as good as a 180, but not too far off them and absolutely fine (probably better than a Turbo/HST) on routes with fairly frequent stops and a 100mph top speed like the North Cotswold Line.  After all, they've been specified to run on diesel on the route beyond Oxford for the foreseeable future.

That sounds about right. The gross power:weight is a little better than an HST, but nothing like as high as a 220 or 180. Its traction should be better than any of them, with more than half its axles driven. How much of that gross power gets to the wheels is one of the unknowns. The others kick in at high speed, where air resistance dominates. Longer is better for this, as the ends are a big drag, so a 9-car 800 should beat an HST. For a 5-car, or two of them, it's less clear - ten cars is good, but a big notch halfway along to screw up the airstream is bad. So it could go either way.

Two little puzzles:

How much energy would be saved by putting a decent faired join between streamlines train units? I'm sure that's not so hugely difficult to do as everyone makes out, and would be as green (but maybe not the new GWR^▸ (Great Western Railway) green). And it would give you bragging rights over TGVs^▸ (Train a Grande Vitesse).

And Hitachi draw their train with 25m carriages and 1m gaps, which would, of course, add to drag. Isn't that a huge gap - far bigger than other trains? Of course, it might be draughtsman's licence. So, if anyone comes face to side with one and has a tape measure on them ...

[Thatcham Crossing]

but it's now 10 minutes longer to London

Not sure what route was being referred to, but I was recently on a 166 that managed PAD^» (Paddington (London) - next trains) to RDG^‡(resolve) non-stop in 29 mins. I think the fastest HST^▸ (High Speed Train)'s do it in 24 or 25.

So if a 90mph Turbo can do it in that time, an 800 (of whatever flavour/speed capability) isn't going to make a lot of difference.

[Billhere]

Horses for courses. I had a cab ride on an HST^▸ (High Speed Train) from Oxford to Worcester and back to Reading a few years ago. The Driver said they struggled over the Cotswolds because of the gradients and the distance between stops didn't allow them time to really get going, and I have to say the engines behind my head didn't sound comfortable.

On the other hand we had a dead stand at Didcot East to let a Turbo go by Up Relief and it was at Goring before we caught it on the Up Main. It was once we actually got to a ton that you could feel the engine stretching out into a gallop, the nearest analogy was a race horse lengthening its stride and was really doing what it was made for. It sounded very comfortable at 125mph.

Never a popular choice with Drivers over the Cotswolds especially with the ones that terminated at Great Malvern and went into the turn back siding at Malvern Wells. Because of complaints from residents they had to switch the London end engine off, and the track wasn't level enough to restart it until they got to Shrub Hill.

An educational trip, and a real eye opener in managing to keep time with a big heavy train in varying circumstances.

[Richard Fairhurst]

Not sure what route was being referred to, but I was recently on a 166 that managed PAD^» (Paddington (London) - next trains) to RDG^‡(resolve) non-stop in 29 mins. I think the fastest HST^▸ (High Speed Train)'s do it in 24 or 25.

Paddington to Reading could be done in just under 23 minutes. I used to regularly catch the 0800 HST from Paddington, and if it had a clear run, I could sprint down Platform 4 as was (I was younger then...) and catch the 0824 to Wokingham from 4A. That was in 1998/9, though, before the advent of defensive driving or Heathrow Express.

Agreed that 800s should fare well on the Cotswold Line, and 802s should be even better.