Current and Proposed New-Builds

From what I've read, it was Raven's answer to what Doncaster was proposing to build - Raven wasn't intending being passed over as CME of the new LNER, and wanted to get his Pacific out before Doncaster got theirs out... This he did, essentially through enlarging the NER Atlantic. The A2s put in some creditable performances, but once the LNER had been formed, they were regarded as a non-standard class - They also suffered from hot-boxes on the rear truck as a result of having inside bearings.
To me, the NER Pacifics (and all other Pacifics & Atlantics with inside rear axleboxes) look rather clumsy, as though the rear wheels were almost an afterthought - 2404 City of Ripon looked more the business after being rebuilt with a Gresley A1 bolier and being paired with a Gresley tender.

Richard.

 

A2 were magnificent. Bit a bit flawed. Deeply unpopular in York shed as one of the worst a lot of wear and tear on a big end and poor driver vision. There faults were never remedied a bit like Robinsons magnificent B3 as they were competition to your own designs. But magnificent. With this and TGB we could have a full house

 

Anyone got a piccie?

..... unless we include pacific tanks on the 'to do' list .... of which we have precisely (hold on, I'll just tot up the numbers) ..... none!

 

Only piccie on t'web that I found was on the LNER Encyclopaedia, the link you put up in your last post... Scroll down to the 3rd. photo.
It also had the trailing truck modified with external axleboxes.

Richard.

 

So it does.... Best put me specs back on!

TBH, though behind the driving wheels it does look good, I'm not quite as enamoured of the inelegant smokebox, it's door or that saddle.

The LNERE entry states the length of the A2's limited their route availability, which seems a bit odd. Where could an A1/A3 run where an A2 couldn't?

Any computer whizz fancy giving one a modernising Thompsonesque makeover ..... just for the hell of it?

 

One more picture of the Raven`s A2 here, in this case it is locomotive no. 2401. :https://pre00.deviantart.net/eaf4/t...401_departing_york_by_rlkitterman-d992c9s.jpg

What strikes me of this class is the very long and almost"naked" boiler.

Knut

 

While I'm nor certain, I doubt that the boiler extended all the way to what visually would be referred to as the smokebox.

 

Behind the drivers, it was essentially a Gresley A1, with a slightly larger firebox, the cab was modified and widened to fit.

There are sections about them in "East Coast Pacifics at Work" by Peter Townend, and "British Pacific Locomotives" by C.J. Allen, both books well worth reading.

Richard

 

I keep looking at the brilliant manipulation of photographs on this site and wishing some of them had been made, or still could be made - I particularly like the A4-derived Atlantics, and the proposed Gresley Pacific created from enlarging the Ivatt Atlantic. The 4-6-0 version looks nice too!
http://www.rmweb.co.uk/community/index.php?/gallery/album/1412-alternative-design-history/

Richard.

 

I was quite taken with the Thompsonised Stirling single.
I'll just get my coat.......

 

What a great site! Thanks for the link!

 

Robinson 9N please! That's LNER A5.

Instead of a Raven A2, how about the *other* development of his Atlantics - the Gresley C9.

 

The boiler was the longest on any British loco I think. Indeed the view down that barrel must have been awesome. It did actually extend all that way. Apparently a lot 'cheaper' than a tapered boiler, but nowhere near as good a steamer. Hence its unfair to compare GW Castles with similar looking Claughtons , Lord Faringdons, Cardeans least on the boilers. The A3 and Princess are more on a parity. But I'd suggest the B3s and A2s were better than any LMS until the Lizzies arrived, they were perhaps unlucky by being grouped with Gresley!

 

Lord Faringdon v Cardean eh? That's like putting Brigitte Bardot up against Sophia Loren and trying to decide which one would have made the best all-in wrestler!

 

There were advantages - and disadvantages - to tapered boilers, but better steaming didn't necessarily follow, as W.A. Stanier proved when he replaced the parallel boiler on the Baby Scots for a tapered one. It's down to correct ratios: grate area, tube length to diameter, etc. Very long boilers present problems in getting the correct length to diameter to give a decent A/S ratio. The original Princess boilers were very long and suffered as a result.

 

I defer to your source, but Locos of the LNER Part 2A p.138 details trials between the A1 1472 and A2 2400 in 1923, the latter having a better boiler performance.

 

Here is a photo of 2401 City of Kingston Upon Hull with an eight-wheeled tender. Can anyone suggest the location?

 

Obviously the valves are between the frames which makes the cylinder block much smaller BUT they do look rather either under cylindered or over boilered

 

Apologies if this is a daft question, but would the geometry of a paralell boiler with the diameter/length ratio similar to the Raven A2 produce a greater temperature differential between throat and tube plates than for a shorter boiler of identical diameter?

 

No apologies needed. As the hot gases travel down the tubes, heat is transferred to the water on the other side of them. The tube length / diameter has to be right to allow it do this along the full length. i.e. all the heat has not been transferred part way along the tube, so that the front ends are cold and not evaporating water; or the heat isn't transferred fast enough and is wasted by being exhausted from the chimney. It's a delicate balance. That is, I know, an over-simplification as there is a lot more involved, but it's a starting point.

Among the advantages of tapered boilers are that they reduce water surge on braking, since there is less space available at the front end to flow into; and there is more water at the rear end subject to heat from the fire. The latter, I suspect, is marginal.