Class 800 - Updates

[D854_Tiger]

There would be no need to use diesel to get under a bridge, it would just be coasted, the same as any other neutral section - and the same as what any proper electric train would do.

 

It depends if wires were to be provided through the neutral section.

 

If the pantograph needs to be lowered and raised I'm guessing it would need quite a bit of railway to do that, more than coasting could allow for.

 

It still sounds like a messy idea to me, just to get under a low bridge, and from a reliability perspective just more to go wrong.

 

A wired neutral section would be simpler and it's not as if there won't be plenty of those anyway.

[Zomboid]

I could see the point of an "air gap neutral section" for something like Sydney Gardens or a swing bridge, but not for a regular bridge.

[jim.snowdon]

The presumption is that the wire can be got below the bridge, but not with the necessary electrical clearances. As far as the letter are concerned, it is not necessarily the clearance between the wire and the bridge that is the problem, but the clearance betwwen the pantograph horns and the bridge on arch bridges.

 

"Air" gaps are a technique not for low bridges, but for swing or lift bridges. Even then it is not a common technique and I have come across only very few outside of the US North-East Corridor.

 

Jim

[jamie92208]

The presumption is that the wire can be got below the bridge, but not with the necessary electrical clearances. As far as the letter are concerned, it is not necessarily the clearance between the wire and the bridge that is the problem, but the clearance betwwen the pantograph horns and the bridge on arch bridges.

 

"Air" gaps are a technique not for low bridges, but for swing or lift bridges. Even then it is not a common technique and I have come across only very few outside of the US North-East Corridor.

 

Jim

 

The article I mentioned makes the point that the real problem is the level crossing just beyond the bridge and that the height requirements for the bridge and the crossing would impose a gradient on the wire that would need a speed limit of 60 mph IIRC.   It's squaring that circle that makes a neutral section of wire a non starter.   However all this is because the problem of the bridge hasn't been solved.   I'm not going to get into that debate as I suspect that competent engineers have proposed several solutions but that what might be called 'political' influences have stalled the work.

 

Jamie

[96701]

It depends if wires were to be provided through the neutral section.

 

If the pantograph needs to be lowered and raised I'm guessing it would need quite a bit of railway to do that, more than coasting could allow for.

 

It still sounds like a messy idea to me, just to get under a low bridge, and from a reliability perspective just more to go wrong.

 

A wired neutral section would be simpler and it's not as if there won't be plenty of those anyway.

With regard to coasting, I was lucky enough to be present on the footplate of a train hauled by either an 86 or an 87 between Carlisle and Preston. After having got up to speed from Lancaster, power would be shut off for Garstang neutral section, and the driver wouldn't need to take power until setting off from Preston, a distance of 9 miles. 

[Geoff Endacott]

With regard to coasting, I was lucky enough to be present on the footplate of a train hauled by either an 86 or an 87 between Carlisle and Preston. After having got up to speed from Lancaster, power would be shut off for Garstang neutral section, and the driver wouldn't need to take power until setting off from Preston, a distance of 9 miles. 

 

That should solve Thingley Junction to Bath then.

 

Geoff Endacott

[D854_Tiger]

With regard to coasting, I was lucky enough to be present on the footplate of a train hauled by either an 86 or an 87 between Carlisle and Preston. After having got up to speed from Lancaster, power would be shut off for Garstang neutral section, and the driver wouldn't need to take power until setting off from Preston, a distance of 9 miles. 

 

Yes, I can easily believe that.

 

An Oxley driver once reliably told me that given a class 8X, a rake of mk1 non-air conditioned stock and clear signals, get through Tring, and you could do the same thing 100 mph all the way into Euston.

 

He reckoned you couldn't do it with mk2s and above but wasn't really sure why.

[Jonboy]

Don’t forget with this talk of coasting that steventon is only around a mile and a half from Didcot in a straight line, and the trains would need to be in a position to coast after a standing start.

[D854_Tiger]

Don’t forget with this talk of coasting that steventon is only around a mile and a half from Didcot in a straight line, and the trains would need to be in a position to coast after a standing start.

 

 As I intimated before, this whole idea of coasting through an air gap just seems like a recipe to have pantographs ending up scattered alongside the GW main line.

[Jonboy]

Make a change from the foundation tubes for the OLE...

[Geoff Endacott]

Don’t forget with this talk of coasting that steventon is only around a mile and a half from Didcot in a straight line, and the trains would need to be in a position to coast after a standing start.

 

That's easy. Don't stop at Didcot.

 

Geoff Endacott

[black and decker boy]

As I intimated before, this whole idea of coasting through an air gap just seems like a recipe to have pantographs ending up scattered alongside the GW main line.

They haven’t proposed an air gap. The bridge will be wired but due to the level crossing, the wire gradient means a severe speed restriction with pan up.

 

All IEP expresses will drop pan, power up diesel and maintain line speed.

 

387s and stopping IEPs will leave pan up and Coast

[Peter Kazmierczak]

Do the diesel engines on an IET need some time to warm-up, or can they be turned-on from cold?

[D854_Tiger]

Do the diesel engines on an IET need some time to warm-up, or can they be turned-on from cold?

 

I've a feeling we are about to find out.

[Coryton]

It depends if wires were to be provided through the neutral section.

 

If the pantograph needs to be lowered and raised I'm guessing it would need quite a bit of railway to do that, more than coasting could allow for.

 

 

Isn't coasting sometimes used on the ECML to get across temporary isolated sections?

 

08 was definitely the right way round on 'opening day' of Class 800 passenger service - if it has become the wrong way round that would be because the two units (08 & 09) coupled have been turned.

 

Having looked at my photographs, I remembered this the wrong way round.

 

As mentioned above, 011 has deputised for 008. As of this afternoon, 011 is facing the correct way but I was distracted as the train pulled out and didn't see which way round 009 was.

 

011 didn't have the electronic reservation system working, but the platform displays in Cardiff were showing a list of 1st class coaches rather than "first class at the rear". Of course giving a list of coach letters tells you nothing about which way round either bit of the train is but it's a start.

 

Curiously, .something in coach A seemed to be making more noise than the engines do under the powered coaches. So perhaps the quiet coach is not so quiet (as well as putting you lower down with respect to the windows than in the powered coaches).

 

I recently had a chance to compare the noise in a Voyager and Mk 4. I was surprised how quiet the engine was in the Voyager - I've never really paid attention before but it was very muted, and I'm not sure how much of what I was hearing was the traction motors.

 

The Mk 4 came off worse - I reckon the air conditioning was considerably louder than anything making noise on the Voyager or on IETs - but the air conditioning noise varied and it's possible it needed maintenance. I was in the end coach on the 225 and the noise from the 91 was also evident.

 

GWR still seem to be using the current IET services to train on-board staff.

 

I came across a rather disgruntled cyclist unhappy at the bike locations being different from an HST and not knowing which sort of train was going to turn up.

 

I was also amused at someone telling their child that they'd picked a bad time to go to the toilet as they couldn't "pull the chain" when the train was in a station. It's nice to know that some people still worry about such things. They seemed a bit sceptical when I said that it didn't matter on the new trains.

[RJS1977]

I've never noticed Voyagers to be particularly noisy either - maybe a bit of a whirr when the driver puts his or her foot down but certainly nothing obtrusive. Generally I've not found them any noisier inside than a Mk3 with one of the vestibule windows open!

[Coryton]

I've never noticed Voyagers to be particularly noisy either - maybe a bit of a whirr when the driver puts his or her foot down but certainly nothing obtrusive. Generally I've not found them any noisier inside than a Mk3 with one of the vestibule windows open!

 

Which is interesting given all the comments about how noisy the IETs were inevitably going to be because they had underfloor engines.

 

I find the interior of the IETs much more pleasant than the Voyagers and I don't think the tilt profile of the Voyagers is entirely to blame.

[royaloak]

This article seems to confirm that the uprated class 800s (effectively a class 802) and the class 802 will have a comparable performance to a HST, when running on diesel, and, of course, much better performance when running on electric.

Does it?

I have read it but havent read that bit, can you point it out to me please.

 

As I read it the 5 coach 800s weigh about 243 tonnes and on full fat engines have 2820hp on tap (3 engines of 940hp each) which give a power to weight ratio of 11.60hp per tonne and gearing optimised for 140mph top speed, whereas a 2+8 HST weighs about 414 tonnes with 2500hp on tap giving 10.86 hp per tonne and is geared for 125mph top speed, while on paper the IETs should keep up to HST timings I think the gearing will work against it enough and I really cant see an IET getting close to HST acceleration above 40mph or top speed anywhere.

 

I understand the sets used on day 1 were full fat engine power, after pulling away from Swindon they only managed 121mph at the BOTTOM of Dauntsey bank, anyway you look at it that is bloomin slow. 

 

Everyone keeps saying they will keep to HST SRTs (they do on the run to Bristol but they are very leisurely timed) but all I see is them struggling pretty much everywhere whereas a HST has power and speed in reserve.

Edited November 4, 2017 by royaloak

[St. Simon]

Do the diesel engines on an IET need some time to warm-up, or can they be turned-on from cold?

 

Yes, there is a warm up period (I'm not sure what exactly it is), the engines are pre-warmed prior to a change-over location, it being triggered by a GPS algorithm.

 

Simon 

[royaloak]

Just about every electric high speed railway there is nowadays has gone over to distributed power multiple units, for the reason you give, plus it's easier on the tracks and provides better performance with more powered axles.

 

Also modern three phase drives are highly efficient and present no real noise problems to bother the passengers.

 

With diesel trains, the locomotive concept still wins over the unit train because they are more efficient on fuel however you need to run trains with more than about six carriages to realise any real difference.

Yeah these 50 tonne per coach IETs are going to be so easy on the track!

A HST power car is only 70.25 tonnes!

 

It doesnt matter how many powered axles you have got if the engines only supply a limited amount of power!

 

Why cant people understand the simple fact that on diesel (whether uprated or not) these things havent got enough power to compete with HSTs on acceleration or top speed!

 

If any of the IET lovers could post some facts showing me how I am wrong then please do,but my experience of actually being in the cab of them while running on diesel says I am right!

Edited November 4, 2017 by royaloak

[royaloak]

Yes, there is a warm up period (I'm not sure what exactly it is), the engines are pre-warmed prior to a change-over location, it being triggered by a GPS algorithm.

 

Simon 

How are the engines warmed up?

 

I do know the answer.

 

Edit-

 

There are two posters in this thread who are posting their opinions as facts (not you St. Simon), nearly every one of their posts is either inaccurate or completely wrong and after reading more of their posts has reminded me why I said I wouldnt bother posting in it anymore.

 

Oh if anyone is interested the IET manual consists of 261 pages, royaloak out, TTFN

Edited November 3, 2017 by royaloak

[3rd Rail Exile]

That's easy. Don't stop at Didcot.

 

Geoff Endacott

Harsh - it's a rapidly expanding town that is already in dire need of a much better service!

[D854_Tiger]

 

Why cant people understand the simple fact that on diesel (whether uprated or not) these things havent got enough power to compete with HSTs on acceleration or top speed!

 

 

 

 

The point is surely that, even with the cut down electrification plan, they won't have to, as all the GW 125 mph stretches will be covered by the overhead wires.

 

If you look at the bits of railway that won't (for the time being) they are all rather leisurely bits of railway where, in any case, the trains are making frequent stops.

 

Even if they are a bit slower say between Bristol and Chipenham, so what, once they reach the wires nearer to Swindon those trains are going to take off and more than enough to compensate for any slower bits.

 

Couple that with those automatic doors, which surely must be worth several valuable minutes, when compared to those slam doors on a HST and we still haven't seen yet what those uprated engines can do, on paper they will not be far short of HST power and they will benefit from forty years more worth of technology in delivering it.

 

Then, if you've ever experienced a HST over the Worcester route, watching the train manager (often with no platform staff to help) struggle with a busy train and those slam doors, at stop after stop, you will pretty quickly see how a class 800 (under powered or otherwise) is going to be a dramatic improvement over a HST.

 

A South Wales express is going to have wires all the way to Parkway eventually, a wonderful racing stretch, after that, through the tunnel, then the Newport stop and all shacks to Swansea I doubt it matters much whether you're on class 800, a HST or a sprinter for all the difference it makes to journey times.

 

Then don't forget the 15 minutes faster journey times that have been promised are based on the new limited stop trains, two of the Cardiff expresses (of the four per hour) are only going to be one stop after Parkway, something the current HST timetable cannot offer for all their power.

 

Similarly with the Bristol trains one (or maybe two) per hour will be via Parkway then just one stop to Paddington, total distance running on diesel will be about five miles.

 

In the meantime, even without the uprated engines, once the electrification reaches Didcot (imminently) matching those HST schedules should be doable, the class 800s are getting pretty close already.

[jjb1970]

I had a look at one of the GWR sets on Monday on my way out to LHR as one was sitting in the platform when I went for the HEX train. A few impressions of mine are that the train looks very impressive externally and the GWR livery is rather classy and based on a brief look inside the interior seems to be much better than most of the early press commentary would lead me to believe. I'm looking forward to having a ride in one.

[Coryton]

I had a look at one of the GWR sets on Monday on my way out to LHR as one was sitting in the platform when I went for the HEX train. A few impressions of mine are that the train looks very impressive externally and the GWR livery is rather classy and based on a brief look inside the interior seems to be much better than most of the early press commentary would lead me to believe. I'm looking forward to having a ride in one.

 

Yes the interior is very pleasant and (in my opinion of course) far better than the current GWR Mk 3 offering. I think a lot of the negative comments were unjustified.

 

Just remember to bring your own cushion. Maybe they should sell them from the trolley.