Green Arrow steam locomotive technical question?

[PaxmanValenta]

Hi
Can anyone tell me what the narrow copper pipe is that runs out of the smoke box and downwards just to the left of the 'Green Arrow' plaque on outside of smoke box.

https://www.flickr.com/photos/55727...8X2-DeU5bk-4BWjFE-3Jf3Hh-7YRkq6-by9Nts-4M5b95

 

[John Webb]

It is only on the one side. Possibly something to do with a lubrication feed to the cylinders?
This loco is part of the NRM's collection - so a look at their website might provide an answer?

 

[sidmouth]

According to my dad:
See part 2A of RCTS LNER series and under Class A1 etc page 41, left hand column of print, 6 lines up from the bottom. From February 1933 the steam cock for the anti-carboniser was transferred to the right-hand side of the smoke box.
This introduced steam to the lubricating oil directly into the steam chest. Stopped the oil from breaking up into carbon bits
So it was a feature of several gresley classes thereafter.