Class 800 - Updates

[D854_Tiger]

Even 802s shouldn't need 125 on diesel, as the B&H is AFAIK no faster than 110.

 

No surprise that they're rapid on electric though. They'd be even better without the diesel engines, as ECML passengers will enjoy.

 

I suspect we all know that extra power of the 802 is rather more to do with how they perform at 45 mph, than 125 mph, when being used for the theme park ride.

[D854_Tiger]

But even expecting an 802 on diesel to match HST times where speed over 110 is needed is probably asking a bit much given the route they were bought for. I thought they had the extra power for getting over the hills in Devon more than for top speed purposes, though it won't hurt that. All the 125 running was supposed to be on electric, where they're 140mph trains (and that gearing won't help with non-electric performance either).

 

Do they actually have any gears?

 

As far as available bhp is concerned the 802 comes pretty close to a HST, near enough as you wouldn't notice, and they should make better us of that power then a HST.

 

But you are correct to state that they might be found lacking over the hills, up against a HST, because someone came up with the bright idea of using two power cars with just five cars.

 

But then that's just cheating, though I'm guessing these new HSTs will have to contend with rather more station stops.

 

What services are planned for these short-formed HSTs, presumably replacing class 158s, and how fare east of Plymouth, will they reach Cardiff.

[Fat Controller]

Do they actually have any gears?

 

As far as available bhp is concerned the 802 comes pretty close to a HST, near enough as you wouldn't notice, and they should make better us of that power then a HST.

 

But you are correct to state that they might be found lacking over the hills, up against a HST, because someone came up with the bright idea of using two power cars with just five cars.

 

But then that's just cheating, though I'm guessing these new HSTs will have to contend with rather more station stops.

 

What services are planned for these short-formed HSTs, presumably replacing class 158s, and how fare east of Plymouth, will they reach Cardiff.

Unless the traction motors are mounted directly on the axles, then there'd be some sort of geared final drive between motors and axles. 

[D854_Tiger]

Unless the traction motors are mounted directly on the axles, then there'd be some sort of geared final drive between motors and axles. 

 

I don't know but is it not the case with modern AC drives that the rotor (the rotating part of the motor) is essentially the axle.

 

Thus providing a friction-less drive and when the motor is running in generator mode friction less braking as well.

 

In short, there exists, as part of the power train, a part that is only thin air, with no mechanical linkage, the linkage being provided only by the three phase rotating magnetic field. 

 

P.S. I am out of my depth here so could be talking complete ********.

[Geoff Endacott]

1A03 Bristol to Paddington this week:

 

Mon 41 late

Tue 24 late

Wed 12 late

Thu 1 late

Fri 14 late

 

Spot the HST.

 

Geoff Endacott

[Geoff Endacott]

1C03 Paddington to Bristol this week:

 

Mon 6 late

Tue 5 late

Wed 1 late

Thu 1 late (HST)

Fri 9 late

 

Better than the up trains, but is does look as though they struggle to keep to HST timings on diesel (which is hardly surprising.)

 

Geoff Endacott

[jim.snowdon]

Yes, except that....

 

First, it would increase the unsprung mass quite a lot, which will go down like a lead balloon with the track and bridge engineers. It would seriously hammer the track.

 

Second, the lower rotational speed of the axle would significantly limit the achievable power, as well as requiring the drive inverters to run at uncomfortably low frequencies.

 

Putting reduction gearing between the motor and the axle solves the second problem, and lays the foundation for solving the first one by allowing the motor and axle to be mechanically separated.

 

Axle mounted motors did turn up on some early electric locomotives, all slow speed, and didn't last long.

 

Jim

[Zomboid]

Traction Motors on (D)EMUs are body mounted these days, aren't they? Final drive to the bogie being via a prop shaft like with a non electric transmission DMU. That's definitely how voyager style trains work.

[Coryton]

Traction Motors on (D)EMUs are body mounted these days, aren't they? Final drive to the bogie being via a prop shaft like with a non electric transmission DMU. That's definitely how voyager style trains work.

 

Wasn't that one of the novel things about the class 91's? Body mounted motors driving via a cardan shaft, rather than having them mounted on the bogies as with previous electric locomotives (APT power cars aside).

[royaloak]

But again don't overlook the fact which I reported that at least one pair of the sets in traffic on Monday were still running with the original power settings for their engines 

Thats interesting, we were lead to believe that they had chosen these 4 sets as they had been uprated to the full 700kW/940hp with all necessary modifications carried out.

 

I hope you are right because from 40mph these things seem rather 'pedestrian' in the acceleration stakes and a 10 coach set running flat out and only reaching a maximum of 121 mph at the bottom of Dauntsey Bank is not funny.

[royaloak]

Traction Motors on (D)EMUs are body mounted these days, aren't they? Final drive to the bogie being via a prop shaft like with a non electric transmission DMU. That's definitely how voyager style trains work.

Some yes, most no.

[royaloak]

What services are planned for these short-formed HSTs, presumably replacing class 158s, and how fare east of Plymouth, will they reach Cardiff.

Penzance to Plymouth/Exeter and others running Cardiff to Taunton with two trains running through, there will be 8 diagrams covering about 600 miles each a day.

Edited October 20, 2017 by royaloak

[RJS1977]

 

1A03 Bristol to Paddington this week:

 

Mon 41 late

Tue 24 late

Wed 12 late

Thu 1 late

Fri 14 late

 

Spot the HST.

 

Geoff Endacott

 

 

Looking at the timings on RealTime Trains, it would appear that the delays occurred mostly in stations (i.e. dwell times) and under the wires on the approaches to Paddington so I don't think it's an issue with the trains not being able to meet HST timings.

[Ron Ron Ron]

With due respect to Mike (Stationmaster) and his no doubt diligent attention to noting the timings, I think a degree of caution needs to be taken here before jumping to conclusions.

 

From what I've read here and in other places on the T'internet, various people are posting timings for the IET's, but I've not seen anyone posting any comparative timings for HST services running around the same time period, or on previous and later services.

There are other selective timings being presented above.

 

So, I wasted a good few minutes of my life this evening, having a look at what has actually happened at certain times this week, using RTT as a source (......I know, a crude device, but it's all I have to hand).

I'm also making the assumption that for the services quoted, the IET diagrams were run by IETs as expected.

I've looked at Tuesday, Wednesday and today, Friday.

I won't include too many examples (I have quite a few to hand), but just to highlight what appears to be the typical record, here are a few....

 

 

First of all today (Friday 20th)

 

Paddington to Swansea. (showing HST services either side of the 2 IET services)

 

1045  HST - 1min late leaving PAD - RDG 1min early - 2 early BPW - on time Newport - 1 early SWA

 

1145  IET  -  1min late leaving PAD - RDG 1min early - 2 early BPW, but 2 late leaving -  3 late CDF - 4 late BGN - 1 late SWA

 

1245  HST - On time off PAD - OT RDG - 1 late BPW,  but OT leaving - 7 late NWP - 6 late CDF - 9 late BGN - 10 late PTA - 12 late NTH - 11 late SWA

 

1345. IET  -  On time off PAD - 2 early RDG, left OT - 3 early SWI, but only 1 early leaving - 2 early BPW, left OT - 2 late NWP - 3 late BGN, 4 late leaving - 6 late SWA

 

1445. HST - 1 min late leaving PAD - OT RDG - 1 early SWI - 4 late BPW, 5 late leaving - 5 late CDF - 7 late BGN, 8 late leaving -  10 late NTH - 9 late SWA

 

I've highlighted in blue what appear to be extended dwell times for the IET

The IET appeared to have faired better than the couple of HST's on similar workings in that time frame.

 

 

Bristol TM to Paddington

 

0600. IET  - OT off BTM - 1 late BTH - OT SWI - OT DID, but 2 late leaving - 2 late RDG, but 3 late leaving -  14 late PAD   (big delay after Slough and Stockley)

 

0633. HST - OT off BTM - OT BTH, CPM & SWI - OT RDG, 1 late leaving - 16 late PAD (same delay approaching Stockley)

 

0900  HST - OT off BTM - 3 late BTH - 3 late SWI - 5 late RDG - 3 late PAD

 

0930  IET  - OT off BTM - 1 late BTH - 2 late CPM, 1 late leaving - 2 late SWI - 1 late DID, 2 late leaving - 1 late RDG - 1 late PAD (although OT passing Royal Oak)

 

1030  HST - OT off BTM - OT all way - 2 early PAD

 

Again, I've highlighted in blue what appear to be extended dwell times for the IET.

No advantage to the HST's there either.

Detailed passing times along the route don't highlight any noticeable differences either.

 

 

 

Earlier in the week on Tuesday (17th).

 

Bristol TM to Paddington

 

0600  IET  -  OT off BTM - 3 late SWI - 8 late DID - 10 late RDG - (then another delay at Stockley) - 24 late PAD   (lots of finger pointing at this one, but.....)

 

0633  HST  - 8 late off BTM - 25 late BTH - 31 late SWI - 38 late RDG - (then Stockley delay) - 47 late PAD ( !!!!!!!! What happened to this HST? )

 

0900  HST  - OT off BTM - 7 late BTH - 9 late SWI - 8 late RDG - (Stockley delay again) - 24 late PAD

 

0930  IET   -  OT off BTM - 3 late BTH - 3 late SWI - 1 late RDG - (a longer Stockley delay) - 27 late PAD

 

 

I could provide more of the same. for other times and services.

It all reads pretty much the same.

Draw your own conclusions.

 

Regards

Ron

 

 

 

.

Edited October 21, 2017 by Ron Ron Ron

[cheesysmith]

Traction motor mounting 101

 

They tried monting the motor as the rotor as the axle, but there was a limit onto how fast they could spin, and the full mass of the motor was on the axle.

 

Then you have nose hung motors, where the motor is pivoted off the bogie and the reduction gears on the axle. In this half the mass is on the bogie and hlf on the axle. This allows the motor to spin faster than the axle, so more power for the same mass.

 

Then you have the HST, with the motor fitted onto the bogie, and a reduction gearbox fitted to the axle. This reduced the mass on the axle even further.

 

Then you have the  APT system, where the motor is mounted in the body, with the gearbox on the bogie, and only the final drive shafts on the axle, resulting in the lowest unsprung mass on the axle, with the mass of the heavy motor after the primary and secondary suspension.

 

The 91 uses the same system as the APT, but with the motors mounted under the body, in the same space as if they were mounted on the bogies, but attached to the body.

 

And finally, yu have resilient wheelsets, as used on the 86. In these there is 2 halfs to the wheel. The gap between the outer and inner wheel is filled with a "rubber" compund to reduce unsprung mass even lower.

[Ron Ron Ron]

 

1A03 Bristol to Paddington this week:

 

Mon 41 late.       

 

Tue 24 late.        the next service 1A04 (HST) @0633 was 47 late

 

Wed 12 late        service 1A08 (HST) @0800 was 13 late

 

Thu 1 late.          no IET running - 1A06 (HST) @0700 was 5 late  -  1A08 (HST) @0800 was 7 late

 

Fri 14 late           only 2 late arriving at Reading - the next service 1A04 (HST) @0633 was 16 late

 

Spot the HST.

 

Geoff Endacott

 

 

 

There you go, I've spotted the HST's for you Geoff.

 

As I said in my previous post, selective data is being used to finger point, when the timings for HST journeys have been equally late.

 

Up services have also been heavily delayed east of Slough and most notably at Stockley (and east of) at times this week.

Also note that Network Rail had been warning that all Cardiff arrivals from Paddington would be up to 9 late (from west of the Severn Tunnel), all this past week.

 

.

Edited October 21, 2017 by Ron Ron Ron

[APOLLO]

For info APT drive arrangement

 

 

Pendolino wheelset shown here - similar - gearbox on axle.

 

http://www.gettyimages.co.uk/detail/news-photo/set-of-wheels-from-a-tilting-pendolino-train-carriage-are-news-photo/155657939?esource=SEO_GIS_CDN_Redirect#set-of-wheels-from-a-tilting-pendolino-train-carriage-are-seen-at-picture-id155657939

 

Is the 800 similar ?

 

Brit15

[royaloak]

The 91 uses the same system as the APT, but with the motors mounted under the body, in the same space as if they were mounted on the bogies, but attached to the body.

Are you sure about that?

 

What are the large cardan shafts that run from the body to the bogies for?

 

I always thought that the 91s were basically an APT power car with cabs., hence them having the same drive system as the APT.

[The Stationmaster]

Thats interesting, we were lead to believe that they had chosen these 4 sets as they had been uprated to the full 700kW/940hp with all necessary modifications carried out.

 

I hope you are right because from 40mph these things seem rather 'pedestrian' in the acceleration stakes and a 10 coach set running flat out and only reaching a maximum of 121 mph at the bottom of Dauntsey Bank is not funny.

 

I was going entirely on what the Hitachi fitters said - that the sets (8 & 9) had not been uprated.  If they have been uprated and still lose time the way those two did then GWR will need some timetable revisions or should be threatening NR with legal action for failing to deliver the wires up above complete with electricity in them.

[cheesysmith]

The 91 has the motors mounted under the body, with short drive shafts to the gearbox mounted on the bogie, with the final drive shaft from the gearbox to the axle. If you look at photos you can actually see the motors mounted under the body. Even the bogies look like the ones off the APT.

 

IIRC the IEP has multiple small, light motors bogie mounted with small gearboxes mounted on the axle. With the traction electronic distributed along the train, you have low static axle load plus using multiple small motors/gearbox give low dynamic axle load (the main reason for low unsprung mass on a axle). The dynamic axle loading will be higher n the IEP than the 91, but the static axle load will be less.

 

Reducing dynamic axle loads and total static axle loads reduces track forces, and reduces track maintenance requirements. The TGV has a maximum static axle load of 17 tonnes with body mounted motors like the APT. The IEP copies the Japanese bullet trains. Even the humble EMUs like the electrostar use bogie mounted motors with a gearbox mounted onto the axle, for reduced track forces, compared to the axle hung motors used by BR on all the early EMUs (just compare what the track was like on the old SR and GE regions, both areas with high EMU miles ).

 

The pendilino uses motors mounted under the body, driving a bogie mounted gearbox, just like the voyager/meridian do. The voyager only has the inner axle of each bogie powered, so only has 50% powered axles (if they had used the BREL P4 design, you could have had 100% powered axles).

 

BR did a lot of research into track forces after the 86s almost destroyed the WCML because unlike the first 100 electric locos (AM1-5) which had bogie mounted motors and a axle mounted flexible drive/gearbox, the BR designed and built 86 had nose suspended motors, for reduced first costs and reduced maintenance costs. These required a lot of research and redesign to cure the fault, with flexicoil secondary suspension (the big springs on each side, a design which has been used on all BR locos since, even the 58 and 60), and resilient wheel sets.

 

PS-If you ask why doesn`t all trains come with resilient wheels, they require more expensive maintenance and can fail, as happened with the German ICE, where the rum became detached from the axle.

[modfather]

The IEP has four traction motors per motor car, mounted conventionally on the bogie frame with a gearbox. I may still have some snaps from my time working at Stoke Gifford for Hitachi.

[Covkid]

Going back to 1A03 this week I think we need to be utterly fair here and acknowledge a few facts

 

Firstly IETs have been tested for quite a period of time prior to service introduction this week, but have been driven by GBRf drivers. It is only starting this week that GWR's own crews have started operating IET in service and these are crew who have just learnt them.

 

AIUI the doors are controlled by a GPS gizmo linked to an onboard database. This database which Hitachi uploaded to the units going into service was based on the platforms NWR intended to have, not that they currently have. Therefore the incident at Bath Spa was apparently based on the train thinking the Up platform was xxx metres long so that it could auto open the doors on x number of vehicles, which wasn't actually the case. 

 

The GWML between Maidenhead and Paddington is a very busy route and there is congestion particularly in the morning peak. It is a fact of life that ever since Geo Stephenson was a youth that trains havn't always run on time. Therefore 1A03 and all other up trains will have been delayed by other traffic.

 

Whilst I am not impressed with the IET concept I think GWR should be given a grace period to get their staff up to experience and attend to niggly problems. In my view the DfT should have specified HST2 with a power car at each end and unpowered trailers in the middle, except a pan / tran passenger car with traction motors at each end, linked to the diesel power car by a bus. You would then a 2+9 dual mode trainset with 16 traction motors per train, and if ever suffcient OLE were erected then the diesel ends could be craned out of the power cars. Sadly that won't now ever happen.  

Edited October 21, 2017 by Covkid

[Christopher125]

I was going entirely on what the Hitachi fitters said - that the sets (8 & 9) had not been uprated.  If they have been uprated and still lose time the way those two did then GWR will need some timetable revisions or should be threatening NR with legal action for failing to deliver the wires up above complete with electricity in them.

 

According to posts on another forum they may have gone for a halfway house - max power when starting away but as the speed increases they gradually return back to 750hp. 

[pete_mcfarlane]

The 91 has the motors mounted under the body, with short drive shafts to the gearbox mounted on the bogie, with the final drive shaft from the gearbox to the axle. If you look at photos you can actually see the motors mounted under the body. Even the bogies look like the ones off the APT.

That's not surprising really, as the class 91 is basically APT mk2, minus the more exotic technologies like tilt and hydro-kinetic brakes. I think it took a bit of redesigning to get the cardan shaft drive in at the front end (due to the cab), and some of the early design increments didn't have the leading axle powered (going on dim memories of a talk on APT technology I attended 30 nearly years ago....)

[Ron Ron Ron]

......In my view the DfT should have specified HST2 with a power car at each end and unpowered trailers in the middle, except a pan / tran passenger car with traction motors at each end, linked to the diesel power car by a bus.

You would then a 2+9 dual mode trainset with 16 traction motors per train, and if ever suffcient OLE were erected then the diesel ends could be craned out of the power cars. Sadly that won't now ever happen.

 

That is more or less what was originally specified.

The Intercity Express Programme (IEP) started out as the HST2 Programme, which was set up specifically to address the long term requirement for a successor to the rapidly ageing HST diesel fleet.

When it was recognised that there would also be a later need to replace intercity electric trains, mainly on the ECML, the programme evolved into the IEP.

 

The requirement that emerged from that programme, was to specify and procure a BR style, standardised and interchangeable fleet of intercity express trains, for use across the whole network .

It would be provided in three versions....

 

Electric - for the ECML and any future use on electrified routes,

Diesel - specifically for use on the GWML to replace the HST fleet (GWML electrification had been completely ruled out at that stage),

Bi-Mode - aimed initially at replacing the ECML HST fleet, for services beyond the wires and for other routes where services ran on both electrified and non-electrified tracks.

 

The resultant IEP specification did not specify how bidders for the contract would configure the traction power for the trains, but the requirement to easily change power sources and for standardised passenger vehicles, inevitably led to designs that placed the electric and diesel power sources in the end driving vehicles.

The winning Agility Trains (Hitachi lead consortium) bid proposed a train not to dissimilar from the HST in layout, which either electric pan & transformer equipment, or diesel engines, in the driving cars, but unlike the HST the traction motors were distributed along most of the train.

Also unlike the HST, due to weight limitation requirements, the driving (power) vehicles would not have traction motors themselves.

 

The electric version would have two driving (trailer) vehicles, containing the pan, transformer and associated equipment at each end.

The diesel version would replace the two electric powered driving (trailer) vehicles with two driving (trailer) vehicles containing the diesel/battery hybrid generator power set (i.e. no overhead AC power capability).

The Bi-Mode interpretation simply used an electric driving power car at one end and a diesel/ battery hybrid driving power car at the other.

 

The intermediate passenger vehicles, complete with traction motors on many axles, would be standardised, regardless of which configuration of power cars was attached at either end.

 

The Driving power cars and therefore the power configuration could then be interchanged as requirements changed.

e.g. A diesel train could be made into Bi-Mode by changing one diesel power car for an electric one. A Bi-mode could be changed to all-electric, or all-diesel accordingly.

 

This is the train that was subsequently ordered by the DafT.

 

Shortly after selecting the Hitachi design, the Labour government of the day performed a complete U-turn on electrification and announced the GWML electrification scheme.

The all-diesel version of the IET was then dropped as it was no longer considered necessary, with the GWML getting electric and Bi-mode versions instead.

It is only at a later date, after much kerfuffle, that the DafT insisted on a complete change of tack and demanded a change to underfloor Diesel engines.

The programme then descended into DafT micromanagement, specification change, excessive meddling and ultimately a massive cost over-run as a result.

 

The more recent debacle over the failure of NR to deliver the electrification programme on time, the huge cost over-run and the subsequent knee-jerk reaction from the DafT, has added more confusion and much increased costs resulting from the need to have all the GWR electric IET's delivered as Bi-Modes instead.

 

 

 

 

.

Edited October 31, 2017 by Ron Ron Ron