Class 800 - Updates

[jjb1970]

I bet GWR will love that, who do they think passengers will blame if the units are underpowered and struggle to operate the timetable, DafT or GWR? That said, DafT have previous on using TOCs as body armour to hide behind and pick up the mess created by DafT, just ask Southern trains.

[D854_Tiger]

I bet GWR will love that, who do they think passengers will blame if the units are underpowered and struggle to operate the timetable, DafT or GWR? That said, DafT have previous on using TOCs as body armour to hide behind and pick up the mess created by DafT, just ask Southern trains.

 

The view seems to be that those HST schedules are already somewhat bloated anyway but, no doubt, for good reason.

 

On a good day, the class 800s should be OK but when things go even slightly **** up ....... they have nothing left spare, unless you count those short (but getting longer) bits with wires.

[D854_Tiger]

 

As for the class 802, it has been designed for the job of WoE, the Hitachi people have their performance graphs, they will configure the software accordingly and I think we can be confident they do actually know what they are doing.

 

 

 

P.S. The top speed currently on the WoE main line is only 115 mph and even then only for short stretches.

 

The extra grunt the class 802s are to have (and more than likely only need) is for use over the Devon banks, having been that way many times with a HST it's probably fair to say all the power in the world isn't a great deal of use when the routes involved are so heavily speed restricted.

 

An HST between Newton Abbot and Plymouth, with two stops, is currently allowed 43 minutes, a Sprinter, with only half the power, 47 minutes, just a four minute penalty.

 

Even a 5 car class 800 would have an extra 100 bhp per coach over the sprinter and the class 802 nearly 200 bhp per coach extra.

 

As an aside a Voyager with only one stop is allowed 39 minutes, a HST 42 minutes, so all that extra power of the Voyager earns you just three minutes, for a HST to match a Voyager it needs to be a 2+5.

 

So the new 2+5 HSTs will only be around three minutes quicker over the banks than the 2+8 version and that's assuming the timings are all to do with power.

 

Seriously, a couple of grannies, struggling with four of five cases at Totnes (no shortage of those that way), and any advantage offered by a HST is pretty much lost, that three minutes a Voyager has over a HST, you do wonder if that's down to the doors, rather than the engines, and the class 802 will at least have the same door advantage.

 

Down that way, with all the stops, the tourist (rather than commuter clientele) and usually just the train manager to handle things on the platform, those automatic doors are going to make life a lot easier than managing all the slam doors on a HST.

[RfDforever]

 

 

Seriously, a couple of grannies, struggling with four of five cases at Totnes (no shortage of those that way), and any advantage offered by a HST is pretty much lost, that three minutes a Voyager has over a HST, you do wonder if that's down to the doors, rather than the engines, and the class 802 will at least have the same door advantage.

 

But the grannies will find one big advantage with the HST; there will be somewhere to put those cases when they get on board....

[Siberian Snooper]

Voyagers seem to be a bit quicker off the mark when they go from a standing start, than a HST.

[D854_Tiger]

But the grannies will find one big advantage with the HST; there will be somewhere to put those cases when they get on board....

 

Blocking the gangways in the Pullman Dining then.

 

I though the 802's were being built to a WoE specification, rather than GW commute to Didcot specification, in which case you would hope someone has thought of that.

[modfather]

...the informed panel does realise only two engines are required to supply the APS. engine three is surplus to normal requirements.

[royaloak]

P.S. The top speed currently on the WoE main line is only 115 mph and even then only for short stretches.

 

The extra grunt the class 802s are to have (and more than likely only need) is for use over the Devon banks, having been that way many times with a HST it's probably fair to say all the power in the world isn't a great deal of use when the routes involved are so heavily speed restricted.

 

An HST between Newton Abbot and Plymouth, with two stops, is currently allowed 43 minutes, a Sprinter, with only half the power, 47 minutes, just a four minute penalty.

 

Even a 5 car class 800 would have an extra 100 bhp per coach over the sprinter and the class 802 nearly 200 bhp per coach extra.

 

As an aside a Voyager with only one stop is allowed 39 minutes, a HST 42 minutes, so all that extra power of the Voyager earns you just three minutes, for a HST to match a Voyager it needs to be a 2+5.

 

So the new 2+5 HSTs will only be around three minutes quicker over the banks than the 2+8 version and that's assuming the timings are all to do with power.

 

Seriously, a couple of grannies, struggling with four of five cases at Totnes (no shortage of those that way), and any advantage offered by a HST is pretty much lost, that three minutes a Voyager has over a HST, you do wonder if that's down to the doors, rather than the engines, and the class 802 will at least have the same door advantage.

 

Down that way, with all the stops, the tourist (rather than commuter clientele) and usually just the train manager to handle things on the platform, those automatic doors are going to make life a lot easier than managing all the slam doors on a HST.

Why are you obsessed with power?

What about gearing?

Have you included that in your calculations?

[The Stationmaster]

The view seems to be that those HST schedules are already somewhat bloated anyway but, no doubt, for good reason.

 

On a good day, the class 800s should be OK but when things go even slightly **** up ....... they have nothing left spare, unless you count those short (but getting longer) bits with wires.

 

There is a fair bit of 'padding' in some current timings and parts of the timetable - but not in the HST SRTs.  Hence my comments about nett times and not knowing what any inability to meet them in particular places might mean to the timetable.

 

For example in my final 'big railway' post, where I was in charge of the company's operations planning, we knew all too well that if one of our trains missed its path on particular parts of the route by no more than 3 or 4 minutes the loss of that part of the path would mean losing the rest all the way to London and that could easily turn into a 10 or 15 minute late arrival which, for a train on minimum turnround in the peak, could hit a subsequent departure before it even started its journey.

[The Stationmaster]

Voyagers seem to be a bit quicker off the mark when they go from a standing start, than a HST.

A Class 165 DMU is quicker off the mark from a standing start than an HST - as you can sometimes see when departing Reading.

[Titan]

Why are you obsessed with power?

What about gearing?

Have you included that in your calculations?

 

Because gearing does not make that much difference, particularly when compared to power on a diesel passenger train?

 

Take a Deltic for example. geared for 105mph max speed, full power available between 18.5 and 100mph.

 

Re gear it for say 75mph, and you will only improve performance below 18.5mph, since tractive effort is entirely dependent on how much power you can get down. As both versions have 3,300bhp, available, they will both put down near as makes no difference exactly the same tractive effort, and therefore acceleration between 18.5mph and 75mph when the 75mph version runs out of puff.

 

However, increase power to 3,600bhp with the same 105mph gearing, and the 3,600bhp version will have better acceleration all the way from 18.5mph up to 100mph and beyond, far more significant than the few mph you gain below 18.5mph that regearing alone would give you.

Edited November 13, 2017 by Titan

[Siberian Snooper]

A Class 165 DMU is quicker off the mark from a standing start than an HST - as you can sometimes see when departing Reading.

I assume the units are quicker off the mark, because they have a greater number of driven axles getting the power down, but the HST has more gee gees once it gets past a certain speed and can continue to accelerate, whilst the unit is pretty much a spent force.

[royaloak]

Because gearing does not make that much difference, particularly when compared to power on a diesel passenger train?

 

Take a Deltic for example. geared for 105mph max speed, full power available between 18.5 and 100mph.

 

Re gear it for say 75mph, and you will only improve performance below 18.5mph, since tractive effort is entirely dependent on how much power you can get down. As both versions have 3,300bhp, available, they will both put down near as makes no difference exactly the same tractive effort, and therefore acceleration between 18.5mph and 75mph when the 75mph version runs out of puff.

 

However, increase power to 3,600bhp with the same 105mph gearing, and the 3,600bhp version will have better acceleration all the way from 18.5mph up to 100mph and beyond, far more significant than the few mph you gain below 18.5mph that regearing alone would give you.

Absolute rubbish.

 

HSTs and IETs are geared differently and gearing makes a huge difference to tractive effort as does adhesion.

 

A good example would be a car driven in 4th and then 5th gear, in your world you are saying it would accelerate at the same rate in both gears up until it hits the redline in 4th gear which is totally wrong.

Edited November 13, 2017 by royaloak

[Zomboid]

An electric motor power/ torque output characteristic is not the same as an internal combustion engine, but nor is it totally flat. A variable frequency drive is closer to flat than a conventional motor (are they DC on a HST?), but ultimately the principle is the same; the torque varies with RPM, so how the final drive is geared has a significant impact.

[royaloak]

HSTs are DC traction motors.

[Titan]

Absolute rubbish.

 

HSTs and IETs are geared differently and gearing makes a huge difference to tractive effort as does adhesion.

 

A good example would be a car driven in 4th and then 5th gear, in your world you are saying it would accelerate at the same rate in both gears up until it hits the redline in 4th gear which is totally wrong.

 

 

It seems you have a total lack of understanding on how a diesel electric transmission works. The motor/generator is the equivalent to the gearbox, providing an effectively infinitely variable gearbox. Changing the gear ratio on a train is like changing the diff ratio on a car, not sticking it in 4th or fifth gear, and the results are exactly as I have described as far as the train is concerned, due to the infinitely variable gearbox the electric motor provides.

Edited November 13, 2017 by Titan

[DavidB]

It seems you have a total lack of understanding on how a diesel electric transmission works. The motor/generator is the equivalent to the gearbox, providing an effectively infinitely variable gearbox. Changing the gear ratio on a train is like changing the diff ratio on a car, not sticking it in 4th or fifth gear, and the results are exactly as I have described as far as the train is concerned, due to the infinitely variable gearbox the electric motor provides.

Interesting. BRCW produced two variants of its diesel electric type 2. One had 75mph gearing and a 1,160hp engine, while the other had 90mph gearing and a 1,250 hp engine. According to published data, the performance curve of the lower-powered locos far exceeded the higher-powered locos in the lower speed range (30mph or so from memory), which is why they dominated the Highland and Far North lines for 20 years, while the higher-powered batch were based in the Central Belt. What am I missing?

 

David

[royaloak]

Interesting. BRCW produced two variants of its diesel electric type 2. One had 75mph gearing and a 1,160hp engine, while the other had 90mph gearing and a 1,250 hp engine. According to published data, the performance curve of the lower-powered locos far exceeded the higher-powered locos in the lower speed range (30mph or so from memory), which is why they dominated the Highland and Far North lines for 20 years, while the higher-powered batch were based in the Central Belt. What am I missing?

 

David

Apparently the same thing I am!

 

A   350hp class 08 has a maximum tractive effort of 35000 lbf

A 2700hp HST has a maximum tractive effort of 17980 lbf 

 

I cant quite correlate horsepower to tractive effort on that one unless the gearing has an effect?

Okay its a rather extreme example but it does show how gearing has an effect on tractive effort, but I am obviously wrong on that as well!

Edited November 13, 2017 by royaloak

[DavidB]

I assume the units are quicker off the mark, because they have a greater number of driven axles getting the power down, but the HST has more gee gees once it gets past a certain speed and can continue to accelerate, whilst the unit is pretty much a spent force.

Isn't it more to do with the fact that the 165 is a diesel hydraulic with a torque converter configured to give good initial acceleration up to 50mph, before the direct final drive kicks in, whereas the HST is a diesel electric geared for 125mph. An HST has more driven axles than a 2 or 3 car Turbo and can show a Turbo a clean pair of heels from a standing start if dropped quickly into notch 5 on clean rails (and especially if running as a 2+7 set, as a number are at present). The Chiltern 165/0s are faster off the mark with their lower 75mph gearing, with the final drive kicking in around 40mph - they could out-accelerate the Met Line A Stock from Harrow-on-the-Hill when the latter were running in outer-suburban weak-field mode.

 

David

[Titan]

Apparently the same thing I am!

 

A   350hp class 08 has a maximum tractive effort of 35000 lbf

A 2700hp HST has a maximum tractive effort of 17980 lbf 

 

I cant quite correlate horsepower to tractive effort on that one unless the gearing has an effect?

Okay its a rather extreme example but it does show how gearing has an effect on tractive effort, but I am obviously wrong on that as well!

 

You have to understand that those tractive efforts are measured at 0mph. Measure the tractive effort at 15mph and the 350bhp 08 would have very little, and the HST will win hands down as it will still be making 17980 lbf. I expect the HST power car will beat the 08 from about 5mph upwards. Why? because to develop tractive effort at any kind of speed it is all down to power.

 

The correlation between horsepower and tractive effort is tractive effort = horsepower/speed, except at very low speed where it is down to the limitations of the motor/generator combination.

 

So apart from low speeds, if you compare like with like - i.e. keep the speed the same, more horsepower = more tractive effort.

 

ie a 3,300bhp Deltic will pull harder than a 3,100bhp class 60 at 40mph all day long, despite the class 60 being able to pull 2 Deltics backwards at 5mph, and in this game it is tractive effort at speed that counts.

Edited November 13, 2017 by Titan

[royaloak]

ie a 3,300bhp Deltic will pull harder than a 3,100bhp class 60 at 40mph all day long, despite the class 60 being able to pull 2 Deltics backwards at 5mph, and in this game it is tractive effort at speed that counts.

Can you provide any evidence to back that up because a 60 can supply a continuous TE of 71570lbf from 17.4mph but a Deltic can only provide a continuous TE of 30500lbf from 32.5mph so I dont see how your statement stands up to scrutiny!

 

The higher the geared maximum speed the lower the TE throughout the rev range.

Edited November 13, 2017 by royaloak

[Titan]

Can you provide any evidence to back that up because a 60 can supply a continuous TE of 71570lbf from 17.4mph but a Deltic can only provide a continuous TE of 30500lbf from 32.5mph so I dont see how your statement stands up to scrutiny!

 

The higher the geared maximum speed the lower the TE throughout the rev range.

 

Like I said, you have to compare tractive effort at the same speed. Find out what TE the class 60 develops at 32.5mph, and it will be less than the Deltic at 32.5mph.

[Geoff Endacott]

Isn't it more to do with the fact that the 165 is a diesel hydraulic...

 

They should have stuck with the diesel-hydraulics in the first place. It would have saved a lot of money.

 

Geoff Endacott

[HillsideDepot]

As it is the first day of the increased class 800 deployment on GWR I thought it worth a check on what was happening.

 

My first “target” was 1C24 (1730 PAD – 2023TAU). I arrived at Chippenham just as the public address was finishing its “shortly arriving at” announcement, which said that the “rear 5 coaches will terminate at Bristol where the train will split”. Whether this will happen was doubtful as “Royal Oak” has said that there are coupling issues and splitting won’t be happening. But the information systems are advising passengers that this will happen, and no harm in starting to get that message out.

 

The LED platform displays have been revised to list not only the first class coach letters, but also now the bicycle areas, wheelchair spaces and quiet coach (singular). The display also says “First class middle and rear”.

As a train which is scheduled to divide, that is also shown on the display some detail, but disappointingly refers only to “front coaches” and “rear coaches” without saying “5”.

 

1C24 arrived at Chippenham 3 minutes late with 800011 leading 800013, both with 1^st class at the London end. The body-side indicators where showing “Taunton”, but throughout both trains. Not helpful when the coaches nearest the barriers at Paddington are stopping 70 miles short of the indicated destination.

Next along was 1C27 (1900 PAD – 2045 BRI) with 800005 leading 800006 due at 2015 but arriving at 2032. Down services seemed to be losing about 10 minutes between Didcot and Swindon, so I’d not put (all?) of that delay down to the class 800. Both units were the correct way round, but had no reservations (electronic or paper).

 

The story was rather a disaster for 1C28 (1930 PAD – 2149 WSM) though. Due Chippenham at 2045 it actually arrived 42 minutes late. However, it departed Paddington 26 minutes behind, having lost 34 minutes on its previous arrival from Swansea, meaning it should have been 6 minutes onto the Down journey when it completed its Up working. That working was a minute down to Bristol Parkway, 5 late at Hullavington, 22 late at Wootton Bassett Junction, 31 late at Swindon, 34 late Didcot and maintaining that to London.

 

800010 (in reverse) was leading 800012 (correct way round), but the engines on 814010 and 813010 were silent. I would assume the driver used all the power available to him on departure, which to my eye was very similar to an “on time” 2+8 HST departure. 1C28 had been overtaken by the following Bristol bound HST at Reading, and eventually arrived at BRI at 2201, 46 minutes late. Not a good day for 800010!

 

The Customer Information System was getting itself rather tied in knots over 1C28. It was advising that “Formed of 5 coaches beyond Bristol” on the scrolling screen, but it was showing as “2045 Bristol Temple Mds & Expected 21xx” as the header. The calling points were showing as “front coaches Bath Spa and Bristol Temple Mds, rear coaches Bath Spa and Bristol Temple Mds”. The PA was similarly confused saying “please travel in the front coaches for” [long pause] “Bath Spa; the rear coaches will detach and terminate here”.

 

Looking at Real Time Trains, 1C28 didn’t go beyond BRI, indeed the 2156 to Exeter appears to have been held for connections out of it (but that is supposition). I wonder if that is the cause of the station CIS confusion? The train side displays were showing Weston-super-Mare though, but if the crew had had more than enough by that point to bother with altering destination displays, they have my sympathies (and the earlier Swindon > Westbury was showing “Swindon” on the front and “Westbury” on the rear, so it’s not a unique problem, and of course had it been an HST the paper labels would still have been showing WSM).

 

My final visit was for 1T35 (2201 BRI – 2224 CPM) which arrived 8 minutes late, having lost time all the way from BRI, and was formed of 43025 + 7 + 43155. This short working has previously been a pair of class 800s, and platform occupation at BRI suggested that it was planned to be today. As it was the set was labled for Paddington – Cheltenham, so presumably had been 1G60 (1742 ex PAD). This then formed 1T32 (2303 CPM – 2331 BRI) back again, although to had to pass signal 1285 at danger as the signaller couldn’t get it to clear.

 

Finally the return of the Taunton, 1A37 (2127 TAU – 0034 PAD) with, as expected with 800011 & 800013. This had a partially working reservation system (some lights green, some out) and the train side displays were blank for most of the dwell time, but then suggested that it was the 06:26 next stop Reading. Half right, then. This time signal 1285 cleared and with a cheery farewell from the Guard off it went into the night.

 

So, rather mixed fortunes, but that’s the reality of running a railway. I hope I have portrayed the above accurately, as a reasonably well informed layman, I trust the professionals on here will forgive any incorrect assumptions.

[The Stationmaster]

Set 80014 noted at Reading today at the Bristol end of an unidentified set - the rear set had the 1st Class formed Bristol end while teh leading set had the 1st in the correct orientation.