GN 4-cylinder Atlantics - some basic queries

[kudu]

Can anyone help me clarify a few points concerning these locos that I am still unclear about from the sources I have available (including the info on this website)?

There were four locos in all, three originally built as compounds.

The first, no 292, has a straightforward history, the only major change being the reboilering described in this website’s section on the C1s.

Next was no 1300 from Vulcan Foundry, with as I understand it four sets of Walschaerts valve gear. In 1917 it was rebuilt as a 2-cylinder simple. Can anyone please confirm (1) whether the cylinders were outside and (2) what valve gear it had and whether it was inside or outside.

The final compound was no 1421, which again I understand had four sets of Walschaerts valve gear. Gresley rebuilt it in 1920 as “a standard C1 Atlantic”, to quote this website, so I assume it then had outside cylinders with inside Stephensons. If this is wrong can someone please put me straight.

Finally, Gresley rebuilt no 279 in 1917 with 4 cylinders. My understanding is that it then had both Walschaerts and Stephensons gear, following the pattern of compound 292 (though without the latter’s divided drive). It then reverted to 2 cylinders in 1937. The website implies cylinders were outside and hints at outside Walschaerts, but again confirmation would be welcome, and correction even more so.

Thanks for any help. And by the way, if anyone has pictures of these locos after rebuilding that would be a real bonus.

Kudu

[john coffin]

Kudu,
basic suggestion is to buy Vol 3A from RCTS GNR loco series by Norman Grove. At this time, they are for sale at around 7.50,
and whilst doing that get vols 1+2 for 6.00 each, all of course plus postage. sadly vol 3B is out of print, and considering how
long the series has been around, nearly 30 years, not sure it will be republished.
3A is about All Ivatt locos, and excludes the best basic information that you are after plus a number of decent photos.


Once you have checked them, then is maybe time to ask more questions.

But basically 1300 was rebuilt as a 2 cylinder simple with Walschaerts and outside cylinders.
The first GNR loco with Walschaerts was 279 a small atlantic after it was rebuilt. It later was rebuilt as a 2 cylinder with inside
cylinders. The others had what you have seen, and all retained outside cylinders.
Paul

[kudu]

Thanks for the info. I'm surprised 279 had inside cylinders after rebuilding.

I may get the RCTS books though I'm trying to limit the growth in my reference books now I'm at the stage of filling in a few gaps in my database of locos in the Grouping. (I'm now drawing on it for a series of articles I'm writing for my local railway society magazine.)

Kudu

[Atlantic 3279]

Checking of sources would definitely be wise here. I believe 279 was in fact the Large Boilered Atlantic, rebuilt circa 1915 with four cylinders as a sort of test bed for the arrangements Gresley was perhaps already considering for an eventual Pacific. Outside Walschaerts valve gear only, with rocking levers transferring the reversed valve motion to the necessary valves for the inside cylinders too. The further 1937 rebuild gave it just two outside cylinders of the K2 general pattern, still with the outside Walschaerts valve gear.

271 was, I believe, the small-boilered Klondike, uniquely rebuilt with inside cylinders.

[john coffin]

sorry guys must keep my typing fingers in better condition.

the small atlantic was actually 271 indeed.

[Pebbles]

In order of building:-

No 271 July 1902. (Based on a small Atlantic format), Four cylinders Stephensons valve gear between the frames activating both outer and inner valves. Rebuilt in July 1911 with two cylinders located between the frames the layout being based on that used on the class D1 4-4-0.

No 292 (compound), Ivatt's first attempt. Four cylinders the inner high pressure cylinders using Stephensons valve gear the layout being again based on that used by the class D1 4-4-0. Outside low pressure cylinders using Walschaerts valve gear. Never re-built and withdrawn in 1927.

No 1300 (Vulcan compound). This whole episode was arranged over Ivatt's head. Very much based on contemporary French design using four sets of Walschaerts valve gear and incorporating Serve boiler tubes. Eventually 1300 was rebuilt in 1917 with two outside cylinders identical to those used on the LNER class K2, this was possible as the outside cylinders had been of a 26inch stroke. Very interestingly this rebuild rather predicted the eventual rebuild of No 279. Withdrawn in 1924.

No 1421 (compound) Ivatt's response to 1300. Four sets of Walschaerts valve gear. Rebuilt in 1920 to standard Large Atlantic.

No 279 Gresley's prototype four cylinder that was eventually superseded by his three cylinder layouts. Because the cylinder stroke was 26inches, as previously mentioned, it was possible to rebuild with two outside K2 type cylinders. It was withdrawn in its original form in 1936 and remerged rebuilt in 1938.

[drmditch]

On a trip to the NYMR last Friday I purchased a copy of O S Nock's 'Great Northern Atlantics' from the Shed Shop - which is always worth visiting.

It contains (on Page 18) a photograph of No.271 in original condition. It has a very 'North Eastern' look about the front end, with the outside cylinders quite tucked away, and all four cylinders driving onto the leading axle. There is also a suggestion (page 21) that it was fitted with Smith segmental piston valves, Ivatt being a friend of Wilson Worsdell. Obviously however, they didn't last very long (1902 to 1905).

Whatever peoples views on Mr Nock, his books are usually interesting!