Hornby Princess Coronation Class (Duchess)

[Guest Midland Mole]

Not sure about that. Power doesn't always equate to speed. It's drag holds you back.

 

Did a streamlined Coronation create more drag than an A4? I genuinely have no idea.

Alex

[DCB]

Did a streamlined Coronation create more drag than an A4? I genuinely have no idea.

Alex

Streamlining makes no appreciable difference to a steam loco and train as they have such a small frontal area compared to length.  They reckon Bugatti over estimated the effectiveness of the Gresley streamlining by a factor of 10 so we are talking 100 hp at those 125 mph speeds.

I think the highest speed ever recorded by a service train with steam in the UK was 108 by a double chimney King on the CRE by Athelney, and by a train with paying passengers 112 down Stoke Bank with Sir Nigel on a SLS or RCTS special.  Both Coronation and Mallard seem to have "Hung" at a certain speed, Coronation around 112 mph Mallard a bit more, Coronation had already run out of track and Mallard only exceeded 120 by over stressing its inside big end.  The only way to settle this argument is a re run, King, MN, Duchess and A4 down Stoke Bank...

Edited November 6, 2017 by DavidCBroad

[Guest Midland Mole]

The only way to settle this argument is a re run, King, MN, Duchess and A4 down Stoke Bank...

 

That would be a glorious thing to behold, if only it was possible.

Alex

[sirwilliamfrs]

There were persistent rumours at the time that 46245 City of London attained 118 mph down Stoke Bank on 9th June 1963 with a Home Counties Railway Society returning special from Doncaster-Kings Cross after a works open day. There appear to have been no accurate timing observers on the train, only stopwatch times taken at random. Unless someone knows different.......! The last reference I can recall in print was in an early issue of RAIL magazine about 1981.

[ikks]

There were persistent rumours at the time that 46245 City of London attained 118 mph down Stoke Bank on 9th June 1963 with a Home Counties Railway Society returning special from Doncaster-Kings Cross after a works open day. There appear to have been no accurate timing observers on the train, only stopwatch times taken at random. Unless someone knows different.......! The last reference I can recall in print was in an early issue of RAIL magazine about 1981.

Nah!!! I was on the train,,,,,timin' it wiv me Timex Hopalong  Cassidy Wotch........ it was 128mph as I observeded  could not be questioned   !!..........beat the duck!! 'ands down

 

Mike

Edited November 5, 2017 by ikks

[Fairburn]

There were persistent rumours at the time that 46245 City of London attained 118 mph down Stoke Bank on 9th June 1963 with a Home Counties Railway Society returning special from Doncaster-Kings Cross after a works open day. There appear to have been no accurate timing observers on the train, only stopwatch times taken at random. Unless someone knows different.......! The last reference I can recall in print was in an early issue of RAIL magazine about 1981.

I remember reading this. IIRC I'm sure the article was about a retiring LMR Inspector, Harry Phillipson?, and the subject had turned to steam locos and they'd taken 46245 over to Kings Cross for the trip. He allegedly put his cap on the speedo clock as it continued to rack up greater and greater speed.

[MikeParkin65]

I am happy to say my second 6256 from Hereford Model Centre is perfect and was tested in front of me when I picked it up yesterday. In addition to the broken body to chassis lug on my previous Rails supplied version that loco also had a wobbly rear driver and the 'false' trailing truck was also lower and downwards pointing. I was willing to ignore both of these faults as problems I could fix. With the increasing cost of models and apparent variations in build quality I am now thinking paying a little extra to purchase relatively locally might be the way forwards for me rather than the hassle of having to send defective purchases back in the post even though Rails have been fine to deal with. 

[Paul_sterling]

Streamlining makes no appreciable difference to a steam loco and train as they have such a small frontal area compared to length.  They reckon Bugatti over estimated the effectiveness of the Gresley streamlining by a factor of 10 so we are talking 100 hp at those 125 mph speeds.

I think the highest speed ever recorded by a service train with steam in the UK was 108 by a double chimney King on the CRE by Athelney, and by a train with paying passengers 112 down Stoke Bank with Sir Nigel on a SLC or RCTS special.  Both Coronation and Mallard seem to have "Hung" at a certain speed, Coronation around 112 mph Mallard a bit more, Coronation had already run out of track and Mallard only exceeded 120 by over stressing its inside big end.  The only way to settle this argument is a re run, King, MN, Duchess and A4 down Stoke Bank...

 

I believe the fastest speed recorded on an "ordinary" passenger service, is by No.2512 Silver Fox, at either 112mph or 113mph, I cant recall which.

[sandwich station]

Except a Gresley one!

 

(Well someone had to say it!)

I was waiting for it.

[Chamby]

Highest HP ever recorded by a British Locomotive.... Coronation, 3,300+hp at cylinders, 2,500hp at the drawbar. (unless anyone knows different?).

Wasnt the LNER 2-8-0+0-8-2 Garratt recognised as the most powerful UK steam loco? Tractive effort was 72,940 lb/ft compared to the Duchess’s 40,000. Not sure how that equates to hp though so you may be right. And the Garratt certainly wouldn’t win any speed trials!

 

Phil

[pH]

Going by tractive effort, a King can.

King at 40,300lbs.

Princess Coronations at 40,000lbs.

Merchant Navy at 37,515lbs.

A4 at 35,455lbs.

 

And the LNER A2 and A2/3 - 40,430lbs 

[sandwich station]

Wasnt the LNER 2-8-0+0-8-2 Garratt recognised as the most powerful UK steam loco? Tractive effort was 72,940 lb/ft compared to the Duchess’s 40,000. Not sure how that equates to hp though so you may be right. And the Garratt certainly wouldn’t win any speed trials!

 

Phil

Yea, get one of those trundling along at 125mph.

[Anglian]

I recall read an article in one of the non modelling railway magazines which presented the case for the unofficial in service speed records reached by the A4's on the ECML when they were making up time. From memory the article covered the great gathering when the A4s were bought back together at York along with some of the crew members. The speeds they reached, as timed by the signal boxes they passed, were enough to get the crews into trouble and they certainly raised my eyebrows well above my head since they were very much higher than the official record. I presumed these stories were true. Does anybody else recall the article?

Edited November 5, 2017 by Anglian

[robmcg]

Highest HP ever recorded by a British Locomotive.... Coronation, 3,300+hp at cylinders, 2,500hp at the drawbar. (unless anyone knows different?).

 

Probably close.

 

All measurements of rate of doing work will have margins of error, so you can argue forever.

 

US steam locos were measured on rolling roads at over 6,000hp  but it does get confusing , some use a term 'developed horse power' and some use drawbar horsepower, and I'm not sure about 'at cylinders', the last might involve a lot of calculation and some assumptions.

 

I prefer 'developed horsepower'  or 'drawbar horsepower', O S Nock in earlier books at least would speak of such as an N15 Arthurs accelerating up a known bank with a known load, or sustaining say 60mph with that load on the bank, and would call it 1,300-1,400hp.  At 60mph the wind factor both had-on and side would have been an estimate. Fair enough, the total weight of the train, and gradient, and speed gives a sensible measure.

 

I think when a Duchess sustains 60mph with 400 tons behind her on a 1-in-75 then the drawbar horsepower would be over 2,000, but of course the 150tons of the engine would mean the developed horsepower was considerably higher, and at speeds like 112mph downhill I think other factors like mechanical integrity come into play!

 

I'm only taking 6th-form maths so other know more than me, my point is that it would help if the test-bed numbers and the real world numbers were used with relevant margins of error.

 

Cheers.

[Chamby]

And the LNER A2 and A2/3 - 40,430lbs

 

.... and the P2 - 43,462.

[Ajax50046]

But tractive effort is just a theoretical calculation of a loco's ability to get a train rolling . An 08 has more than a 67, but you wouldn't call that more powerful. And loco's will exert their maximum tractive effort without their throttles wide open.

 

Be very exciting to see just how well the P2 performs if they sort the issues with it's valve gear. The increased psi boiler for the A1 can already produce more steam that the cylinders need at speed, add a bigger grate, a cylinder diameter almost identical to a Duchess, plus it's Kylchap exhaust...it could well be a contender for the crown. 

 

It will never happen but I would love to see the ECML opened up to race the big steam engines. A1, Duchess, 71000 and the P2. We all know the A4 holds the speed record, but few people would contest that given the same conditions that Mallard had, Coronation would have walked all over it. Incredible machines that really needed mechanical or oil firing to reach their full potential.

[JSpencer]

But tractive effort is just a theoretical calculation of a loco's ability to get a train rolling . An 08 has more than a 67, but you wouldn't call that more powerful. And loco's will exert their maximum tractive effort without their throttles wide open.

 

 

 

 

 

I am always amazed that this theoretical calculation never takes into account the engines adhesive wait. In the early days of steam, it might be irrelevant as the loco could have been - with its then  lower  boiler pressures - hard pressed to cause wheel spins, but Bullied's were light compared to their horse power.

Once the wheels start slipping you have reached the practical maximum tractive effort. This would be easy to calculate (the adhesive weight is known as it the friction of wheel against the rail - you can calculate the force need to break that and cause the wheels to slip - that is then the true max effort providing it is inferior to the standard tractive effort calculation value).

 

A Duchess has lower tractive effort than most type 4 diesels but their horse power was all but equal to a type 5.

[Ajax50046]

Perhaps off topic, but still about Duchesses.  I wonder why the LMR didn't double head Duchesses (i.e. two Duchesses) and only rarely had them piloted, whereas Scots were double headed quite frequently.  Super power for sure, equivalent to at least two class 50s, so performance over the section between Preston and Glasgow would have been quite transformational.

 

Wasn't there a ban on Lizzies double heading due to lack of visibility for the crew of the second loco? 

 

My late school teacher used to swear blind that he was on a big troop train during the war that was double-headed by two streamlined Duchesses. I really wish I'd gotten more detail out of him, and unfortunately i've never seen seen anything recorded on it in the archives either. It must've been some sight and sound climbing Shap!

[Hroth]

Streamlining makes no appreciable difference to a steam loco and train as they have such a small frontal area compared to length.  They reckon Bugatti over estimated the effectiveness of the Gresley streamlining by a factor of 10 so we are talking 100 hp at those 125 mph speeds.

I think the highest speed ever recorded by a service train with steam in the UK was 108 by a double chimney King on the CRE by Athelney, and by a train with paying passengers 112 down Stoke Bank with Sir Nigel on a SLC or RCTS special.  Both Coronation and Mallard seem to have "Hung" at a certain speed, Coronation around 112 mph Mallard a bit more, Coronation had already run out of track and Mallard only exceeded 120 by over stressing its inside big end.  The only way to settle this argument is a re run, King, MN, Duchess and A4 down Stoke Bank...

And to make matters entirely sure, City of Truro too...

[Brocp]

I don't know of a single photo of two duchesses, let alone streamliners, at the head end. There are very few of them being piloted (I know of one where the Duchess is actually the pilot), so I would have to surmise that any claims of a double header would at this stage have to be apocryphal, although definitely wonderful (!)

In the war they may have had a couple of double headed runs, but LMS policy was that class 7 locos (Princesses and Duchesses) weren't to double head together. I've got plenty of pics of Duchesses with smaller classes double heading, from Midland 3Fs to Stanier Tanks and Black Fives but never together and I've only seen one pic of a Princess double heading and that was with a Class 4 Tank very late in their BR lives.

[Arthur]

 

Not a Duchess double header but a Pacific double header. In one of the R. Preston Hendry albums, (The Colour of Steam IIRC), there’s a photograph of a Britannia double heading a red Duchess on a heavy parcels train at Rugby.

 

.

[Paul_sterling]

In the war they may have had a couple of double headed runs, but LMS policy was that class 7 locos (Princesses and Duchesses) weren't to double head together. I've got plenty of pics of Duchesses with smaller classes double heading, from Midland 3Fs to Stanier Tanks and Black Fives but never together and I've only seen one pic of a Princess double heading and that was with a Class 4 Tank very late in their BR lives.

 

I can recall an instance of a Duchess being paired with a Jubilee, although it was the terrible Harrow and Wealdstone crash, where Winward islands and City of Glasgow were hauling the express. 

 

Paul. 

[Paul_sterling]

Not quite, the Jubilee was piloting Princess Anne, City of Glasgow was on its own.

 

Thanks, minor muddlement

 

In my defence, by that point 46202 was all but a Princess Coronation, it was built up of a match up of Princess and Princess Coronation bits. The bottom end was Coronation, and the top end a modified princess with the coronation superheater. 

 

Paul. 

[vitalspark]

Well I cracked for one of these Ivatt Duchesses. Possibly the ultimate UK express power. I am always surprised BR did Duke of Gloucester than a BR version of these.

 

Anyway here are pics :

 

First surprise Hornby provide twice instructions on how to remove the tender body! (This is not a complaint just an observation).

image.jpg

 

Four Hornby Duchesses side by side. Bottom, 1977s Duchess of Sutherland, this is the only one with working lamps. A 90s Duchess, tooling on the front was changed to from the sweeping up of Sutherland to cut through. Top, one of the last previous versions of Hornby's Duchess, City of Edinburgh in Semi form. Just below her, the new Sir William Stanier. The original tender drive ones had no mould joint running across the dome and top feed, while the last loco drive previous version did. This is fixed on Stanier.

image.jpg

 

Comparing the two cab interiors between Stanier left and Edinburgh right. In practice you won,t see these interiors on the layout, even if the cab roof vents can open (by about 2mm) on Stanier, unless you have set track curves.

image.jpg

 

The front bogie is greatly improved on the new model being sprung/attach to the loco chassis in the middle rather than a long slim bar running backwards to between the front drivers of the previous model. The new model has sand pipes too.

 

image.jpg

 

On the previous version, the coal could be removed while the new Stanier has reverted back to a tender full of moulded coal with no option to remove it or see the trimming part. (The recent Merchant navies also have removable coal).

Edit: the coal can be removed from Stanier to reveal the coal pusher. But not very easily.

 

image.jpg

 

Overall the model is better than the previous one before, it is heavier, but not as heavy as a Britannia. While better, this model shows the last previous ones were very good. In most visible areas, other than those sited above, there is little to choose between them. Did Hornby loose the previous tools?

Still very happy with my Ivatt version, and equally happy with the older City of Edinburgh.

 

You didn't mention the correct drivers..surely the biggest improvement of them all.

[farren]

That was why Anne was scrapped and not Glasgow. Glasgows own main frames were bent, so Anne's were used. Some of Anne's workings were total right offs. And being one offs it was more economical to re-build Glasgow.

Edited November 6, 2017 by farren