Intercity Express Programme (IEP) - ongoing discussion

[whole diary]

[Gordon the Blue Engine]

I thought 560 was the de-rated version, with 700 being the full version? Happy to be corrected though

Adelante, I think you’re right, 700 kW is the full version.  Still waiting for confirmation that they'll be running at 700 kW.

[stuving]

"Now, Mrs. IET^▸ (Intercity Express Train), to the sensitive issue of your weight. I see you have been weighed, and had the weights painted on your ends." And those weights are: 47.8 + 50.1 + 50.3 + 50.6 + 51.7, total 250.5 t.*

The weight of IETs was sensitive, if you were following what Roger Ford had to report, or what was discussed here; are these really the light-weight trains we were promised? It does affect performance - you first thing you write on the back of your envelope (or "model", as I call it) is P=mva, where m is mass.

Wikipedia still says a 5-car 800 is 300 t, citing a Roger Ford e-zine, but adding "better source needed".  As that e-zine says "A 60 tonne Diesel Electric Multiple Unit vehicle could not be right" you can see why! In fact, Roger goes on to say "A 20 m long Class 395 Javelin intermediate Motor Second coach with 66 seats weighs 45.7 tonnes. Hitachi has produced a 66 seat 26m long vehicle with an 8 tonne 700kW (938hp) diesel power pack under the floor for a tad over 3 tonnes extra" - or about 49 t. That was based on the marked shipping weight on a carriage arriving from Japan.

I've been using a figure of 240 t, implying the two trailers total 93 t. But that 49 t was shipping weight, and for running weight we should expect quite a bit more. Did the 49 t figure allow for that? I don't know, though it should have done to give a like-for-like comparable figure. Anyway, now we know it's a bit higher than I thought. The requirement has a maximum delivered weight of 249.3 t, and assuming that "delivered" means no fuel they meet that easily.

You can see there is a big effect of having four big indivisible lumps on a 5-car train, but not how much a motor or transformer weighs. It looks as of the transformer plus pantograph weights more than four motors, one engine, plus fuel and the traction/auxiliary power system. But of course if one carriage is left empty-handed, as designer you'll want to offload into it everything you can from the others.

I've assumed the weights marked on carriages are ex-depot, ready to board, i.e. fully loaded with fuel and other supplies, but excluding passengers. (Does anyone know if that's true?)  Passenger load, according to the performance modelling data in the requirement, is 80 kg per passenger and 108 passengers per middle car (8.64 t) and 88 per driving car (7.04 t). Note that is overfull (500 for 315 seats); presumably such a worst case was needed to make sure high passenger loads don't compromise the timetable.

That's more than I realised: 25.2 t (10% extra) even for a just-full load of 315! 10% is not a huge difference, and will mainly impact acceleration and hill-climbing not speed on the flat. But a full train will struggle a bit relative to an empty one (I may revisit my estimates to quantify that).

(* Assuming I managed to remember all five numbers until I could write them down, of course.)

[JayMac]

I think it's worth noting that Roger Ford (sainted by many - not me) has been mostly anti-IEP^▸ (Intercity Express Program / Project.),  almost from day one.

Are his facts and figures rigorously peer reviewed, or just wobbled through the prism of his pre-conceived conclusions?

[grahame]

"Now, Mrs. IET^▸ (Intercity Express Train), to the sensitive issue of your weight. I see you have been weighed, and had the weights painted on your ends." And those weights are: 47.8 + 50.1 + 50.3 + 50.6 + 51.7, total 250.5 t.*

So let me see than in pictorial terms ...

+ = 47.8

+ + = 50.1

+ + = 50.3

+ + = 50.6

+ + = 51.7

[stuving]

So let me see than in pictorial terms ...

Up to a point ... each end car has a pantograph, but only one has a transformer. I can find a picture of an ABB traction transformer, though as Hitachi didn't list a supplier for this item I guess they make their own. Either way, it'll have to go under the floor.

You'll also need to find a picture for miscellaneous electrical bits, both in boxes and (you'll likely find this easier) in a rack of servers, comms, and other train-wide systems - those are the bits I expect to be in the "light end" car.

[stuving]

I think it's worth noting that Roger Ford (sainted by many - not me) has been mostly anti-IEP^▸ (Intercity Express Program / Project.),  almost from day one.

Are his facts and figures rigorously peer reviewed, or just wobbled through the prism of his pre-conceived conclusions?

His opinions we can all take or leave. However, I find he is well-informed, and is enough of a professional to try to get his facts right and to give his sources when he can. In any case, I mentioned him primarily as Wikipedia's source. While railway information there is - er - copious, and generally reliable, in this case the source wasn't even correctly read.

* You don't really think I mean "professional journalist" do you? More like "professional engineer", or perhaps at a push "professional technical journalist".

[broadgage]

Only slightly O/T, but several people believed, and may still believe, that "broadgage" is an assumed name of Roger Ford ! I was most flattered by the comparison.
As whether or not Mr Ford was flattered by the comparison, we know not, but I doubt it.

Part of my sigline is however IIRC^▸ (if I recall/remember/read correctly), a quote from an article by Roger Ford, "capacity on inter city routes should be about number of vehicles, not compressing people"

[JayMac]

Only slightly O/T, but several people believed, and may still believe, that "broadgage" is an assumed name of Roger Ford ! I was most flattered by the comparison.
As whether or not Mr Ford was flattered by the comparison, we know not, but I doubt it.

Part of my sigline is however IIRC^▸ (if I recall/remember/read correctly), a quote from an article by Roger Ford, "capacity on inter city routes should be about number of vehicles, not compressing people"

Well, we will have a net gain of intercity 'vehicles' on the intercity routes out of Paddington. Vehicles with more seats and more legroom.

[stuving]

... The requirement has a maximum delivered weight of 249.3 t, and assuming that "delivered" means no fuel they meet that easily.

"Delivered weight" is actually defined in the requirement:

Delivered Weight:
Means the train weight for the interior configurations defined in Annex D and excluding the following;
a) Emergency equipment that shall be supplied by the Relevant Operator;
b) fuel and fuel additives;
c) toilet water;
d) toilet consumables;
e) catering consumables (including potable water);
f) passengers, train crew and luggage; and
g) Relevant Operator supplied catering equipment.
For the purposes of this definition toilet retention tanks are assumed to be empty.

That's pretty much what I had assumed. Some of the items look a bit petty - like fuel additives. However, the NRMM stage IIIb diesel engine needs urea injection kit so that's another little tank to fill. 

If the trolleys are (as they say) supplied by Hitachi, are they not Operator supplied? Or perhaps not relevant? Or is GWR^▸ (Great Western Railway) not a relevant operator?

Never mind, in any case the only sizeable thing on the list (apart from people and luggage) is the fuel. If this is really 1.55 m³ per engine, that's nearly 4 t in all.

[SandTEngineer]

This was posted on the WNXX^▸ (Stored Unserviceable, Mainline Locos HQ All Classes) Forum......
https://mobile.twitter.com/GWRHelp/status/935188418652524544/video/1

[JayMac]

This was posted on the WNXX^▸ (Stored Unserviceable, Mainline Locos HQ All Classes) Forum......
https://mobile.twitter.com/GWRHelp/status/935188418652524544/video/1

An excellent visual comparison of the acceleration of an IET^▸ (Intercity Express Train) v HST^▸ (High Speed Train).

260m (2x5 car, 600 tonnes approx) IET taking 32 seconds to clear the platform. 224m (8+2 400 tonnes approx) HST taking 51 seconds.

[Electric train]

This was posted on the WNXX^▸ (Stored Unserviceable, Mainline Locos HQ All Classes) Forum......
https://mobile.twitter.com/GWRHelp/status/935188418652524544/video/1

An excellent visual comparison of the acceleration of an IET^▸ (Intercity Express Train) v HST^▸ (High Speed Train).

260m (2x5 car, 600 tonnes approx) IET taking 32 seconds to clear the platform. 224m (8+2 400 tonnes approx) HST taking 51 seconds.

The IET advantage of having axel mounted  variable frequency drive  3 phase induction traction motors (no gears) over the HST noise suspended series wound dc traction motors (with gears).  Also over the 40 odd years since the HST was designed traction control has leaped forward the IET is as different to the HST in this respect as the HST was to the class 47

[Thatcham Crossing]

260m (2x5 car, 600 tonnes approx) IET^▸ (Intercity Express Train) taking 32 seconds to clear the platform. 224m (8+2 400 tonnes approx) HST^▸ (High Speed Train) taking 51 seconds.

And that was under diesel propulsion, presumably an even bigger improvement if the 800's were on the juice?

[stuving]

260m (2x5 car, 600 tonnes approx) IET^▸ (Intercity Express Train) taking 32 seconds to clear the platform. 224m (8+2 400 tonnes approx) HST^▸ (High Speed Train) taking 51 seconds.

And that was under diesel propulsion, presumably an even bigger improvement if the 800's were on the juice?

No - neither train can use its full power at low speeds. Power = speed x traction force, and when it starts the traction force has to be limited to what friction between wheel and rail can provide. That traction force is also likely to be more accurately controlled to be constant over the speed range with the newer trains.

The main difference between those two trains is that low-speed traction force (at the rail). That is set by the assumed coefficient of friction, multiplied by the fraction of the train's weight on the powered axles. That gives a maximum acceleration that is built into the motor controller (either explicitly in software, or by implication in the hardware design). And that "mass-on-motors" fraction is 0.6 for the 800s, but only about 0.33 for an HST. We know that the 800s' design was for a maximum acceleration of 0.7 m/s².

The speed at which prime power becomes a limit depends on the balance of power and traction, and is lower for the 800s - around 45 km/hr versus 90 km/hr for the HST. If the 800 set off at its full 0.7 m/s² it would do its own length in under 28 s - faster than in the video - but by then it would have reached its power limit (unlike the HST), so its acceleration would have had to reduce for the last few seconds.

[Thatcham Crossing]

ok, thanks for the detailed explanation. Great that there are some people who really know their stuff on this forum :-)