Intercity Express Programme (IEP) - ongoing discussion

[whole diary]

[broadgage]

What happens at ambient temperature of 40 degrees ? entirely achievable in the southwest even if improbable in Stonehaven.

Really? That's a higher air temperature than has ever been recorded in Britain, let alone for for the southwest where the official record is 35.4 deg.

In any case, on the few rare days that happens, the risk of track buckling is such that trains will be hit by a lot of speed restrictions.

Incidentally, the main effect of high and low temperatures will be a high auxiliary load, all of which has to be supplied by the diesels when self-powered. Obviously that's worse for the cold limit, as heating will take more power than cooling.

With fewer engines than cars, the auxiliary load takes away a higher fraction of prime power than in a 180 or 220. And don't those use engine exhaust heat for the train cabins? I'm assuming that would help too little to be worth doing on 800s. I'm also assuming Hitachi are not being really sneaky, and using reversible chillers - though it's not impossible.

There are other tricks that can help - for example the option of shutting down heating (or cooling) during the relatively short periods of full acceleration. Again, I have no idea if that is included.

My estimated maximum air temperature of 40 degrees is indeed appreciably in excess of the highest recorded by the Met office. Met office stations are generally located in relatively open country, and at a height of five feet IIRC^▸ (if I recall/remember/read correctly). The thermometer is shaded from direct sunlight by a Stevenson screen.
IMHO^▸ (in my humble opinion), temperatures to which a train is subjected could easily reach 40 degrees at engine height and in a cutting and subjected to sunlight. Even worse would be with another train adjacent and adding heat.
As an example, I have measured an air temperature of 41 degrees in the shade*
I suspect that high temperatures may be a problem for these new trains, as with other new DMUs^▸ (Diesel Multiple Unit).

[4064ReadingAbbey]

The UK^▸ (United Kingdom) plant is just an assembly plant, the bodyshells for the entire fleet were always supposed to be built in Japan; something about the welding technique being a trade secret that isn't allowed to leave Japan I think. The 800 pictured in the link does look like more than just a bodyshell though as stated above.

If I can trust my memory the welding technique is called 'friction stir' and uses a rapidly rotating rod to generate friction heat to fuse the metals together. If it is what I am thinking of, the process was originally developed by the British Welding Research Association/The Welding Institute but I can't remember when...

I expect that the process and procedures used by Hitachi are trade secrets, but the concept certainly isn't.

[IndustryInsider]

I suspect that high temperatures may be a problem for these new trains, as with other new DMUs^▸ (Diesel Multiple Unit).

Extremely high temperatures will no doubt be a problem for these trains, as with all other trains including those with underfloor engines and those with a traditional 'normal' locomotive.  As 'stuving' pointed out, the infrastructure often can't cope with those rare days either.  Fortunately (or unfortunately for sun worshippers) it rarely gets really hot here, so as long as they can perform under high temperatures, by which I mean where the shaded thermometer is reading around the 30c mark, at a better level than, for example, the Class 180s then that is acceptable in my opinion. 

The engines need to be reliable as a failure of one of them reduces power levels dramatically, unlike on a 180 where it makes little difference if one if not working.  I would be interested to see the performance figures of a 5-car IET^▸ (Intercity Express Train) unit running with just two engines working, and how that compares with a HST^▸ (High Speed Train) running on one engine only.  Of course, if you have a single source of power, like on a traditional locomotive, then it's 'game over' should there be a failure, so for that reason alone more than one engine is necessary in my opinion.

[Gordon the Blue Engine]

What is the “electrical interference” problem being experienced?  Is this affecting other equipment on the train, or other railway equipment eg signalling, or local residents eg TV goes funny when an 800 goes by?

I understand that the electrical interference problem with the Class 80x is to do with the lineside telephone system, and that this needs to be fixed before they enter service under electric power.

Whether this is only between Reading and Didcot or on other stretches of the GWML^▸ (Great Western Main Line) as well I do not know.  Presumably this problem did not occur on the testing runs on the ECML^▸ (East Coast Main Line).

[SandTEngineer]

What is the “electrical interference” problem being experienced?  Is this affecting other equipment on the train, or other railway equipment eg signalling, or local residents eg TV goes funny when an 800 goes by?

I understand that the electrical interference problem with the Class 80x is to do with the lineside telephone system, and that this needs to be fixed before they enter service under electric power.

Whether this is only between Reading and Didcot or on other stretches of the GWML^▸ (Great Western Main Line) as well I do not know.  Presumably this problem did not occur on the testing runs on the ECML^▸ (East Coast Main Line).

....ah, but is it the telephone system or the train that's at fault.....

[TonyK]

....ah, but is it the telephone system or the train that's at fault.....

The better question would be "Which is the cheaper to amend?"

[stuving]

....ah, but is it the telephone system or the train that's at fault.....

The better question would be "Which is the cheaper to amend?"

In practice yes - because otherwise you need to answer "which is out of spec?", and that's a notoriously difficultimpossible question. You can write EMC^▸ (ElectroMagnetic Compatibility) requirements for potential sources and victims, but they have to be in terms of defined impedances, coupling properties, etc. It's hard to make that kind of test set-up even in a lab, and you can't really even measure those things on a full-size bit of railway.

[TonyK]

A job for the theorists first, then, although I would have  thought they would have had a good run through the equations long ago.

[SandTEngineer]

A job for the theorists first, then, although I would have  thought they would have had a good run through the equations long ago.

Well BR^▸ (British Rail(ways)) managed to do it back in the late 1950s.......

When I used to maintain the signalling and telecoms equipment at the south end of the West Coast Main Line back in the 1970s we, and drivers who used them, never used to bother about Signal Post Telephones (SPTs^▸ (Signal Post Telephone)) that had a constant buzzing noise on the circuit caused by OLE^▸ (Overhead Line Equipment, more often "OHLE") interference.  You just ignored it....

....and wearing a plastic mac, standing under the OLE on a wet day, kept you awake and alert with a lovely tingle that passed down from your shoulders to feet

[IndustryInsider]

An interesting post from 'Clarence Yard' on railforums.co.uk, who has been closely involved in testing of the new trains, indicates that an unmuzzled IET^▸ (Intercity Express Train) running on diesel power is able to reach 120mph and pretty much match existing HST^▸ (High Speed Train) point-to-point timings - 105mph was reached with one engine isolated, which is still pretty impressive.  Muzzled and the performance was described as anaemic!  Let's hope the DfT authorise unmuzzled working at least until the Cardiff electrification is completed.  Talks are still ongoing apparently.

[ChrisB]

fyi, in case anyone feels like posting that whole post here, is that the figures given are/were considered confidential (by GWR^▸ (Great Western Railway) at least) as obviously are any details on the on-going discussions between GWR, Angel Trains & the DfT^» (Department for Transport - about). There are obviously cost implications involved.

[Gordon the Blue Engine]

The info that came from another forum on max speeds on muzzled and unmuzzled diesel is different from what I’d heard.  So personally I’m taking any “leaks” with a pinch of salt.

[stuving]

I thought I would do a performance comparison of 80x/HST^▸ (High Speed Train) based on the modelling data I've got, to see if it looks similar to those reported figures. I've worked out the time to 100 mi/hr on the level, and the steepest gradient 100 mi/hr can be maintained up, for each type. Obviously the numbers come with a warning that I'm copying them from the back of an envelope that's covered with damp fingerprints.

HST (2+8):       262s, 1/119
muzzled 800      312s, 1/172
unmuzzled 800   226s, 1/111
electric 800      113s, 1/62

That looks pretty similar to what's been reported. Note that a 9-car would be a bit better than a 5-car at high speed, but on my assumed parameters it's not a lot. A 2x5-car is in between the two.

In general, the figures reflect the known facts: on power or power/weight the 802 is similar to an HST, but has better adhesion and low-speed traction, but with 80% of the power it's clearly worse, while  mains electricity provides a lot more oomph than any diesel.

I've not made any assumption about how much power goes into auxiliaries, and I wonder what has been done for trials. The biggest power users are heating and cooling, and if the heating is all-electric that's the bigger. But I don't have any reliable figures for the power required - the best I have is 20-50 kW (all uses) per car. Significant, but not enormous, and variable. And it would affect HSTs and diesel SETs^▸ (Super Express Train (now IET)) much the same, but has no effect when running off mains.

[Tim]

I've not made any assumption about how much power goes into auxiliaries, and I wonder what has been done for trials. The biggest power users are heating and cooling, and if the heating is all-electric that's the bigger. But I don't have any reliable figures for the power required - the best I have is 20-50 kW (all uses) per car. Significant, but not enormous, and variable. And it would affect HSTs^▸ (High Speed Train) and diesel SETs^▸ (Super Express Train (now IET)) much the same, but has no effect when running off mains.

Presumable, with a sophisticated new train, it would just be a matter of writing the correct software code to have the heating/aircon switch off for a couple of minutes when max acceleration was needed?

[Electric train]

I've not made any assumption about how much power goes into auxiliaries, and I wonder what has been done for trials. The biggest power users are heating and cooling, and if the heating is all-electric that's the bigger. But I don't have any reliable figures for the power required - the best I have is 20-50 kW (all uses) per car. Significant, but not enormous, and variable. And it would affect HSTs^▸ (High Speed Train) and diesel SETs^▸ (Super Express Train (now IET)) much the same, but has no effect when running off mains.

Presumable, with a sophisticated new train, it would just be a matter of writing the correct software code to have the heating/aircon switch off for a couple of minutes when max acceleration was needed?

The trains "hotel" load is fairly insignificant to the traction load, for a whole train the hotel load 200 to 500kW traction load 2 plus MW