LNER J52 0-6-0ST safety valve position

[Haddocksrock]

I am building a Beaver N gauge J52 kit and completing it in BR 1950's condition. 

My query is the positioning of the safety valves they appear from photos to be exposed (as in not in a cover) and placed on top of the tank plating but these are pictures taken from the side or track level.

The one picture I have taken from above is slightly indistinct but appears to show them in a circular hole (pit) recessed in the tank top?

The Hornby model has them on the tank top which is flush and flat.

Anybody have any idea on which is the correct positioning or is either correct depending on individual locos?

Edited August 6, 2021 by Haddocksrock
Clarification (hopefully)

[doilum]

7 hours ago, Haddocksrock said:

I am building a Beaver N gauge J52 kit and completing it in BR 1950's condition. 

My query is the positioning of the safety valves they appear from photos to be exposed (as in not in a cover) and placed on top of the tank plating but these are pictures taken from the side or track level.

The one picture I have taken from above is slightly indistinct but appears to show them in a circular hole (pit) in the tank top?

The Hornby model has them on the tank top.

Anybody have any idea on which is the correct positioning or is either correct depending on individual locos?

Without searching my archives I seem to remember that there were some variations. At least two batches? Which individual locomotive are you aiming for?

Having had a look, there isn't much in the RTCS green bible to help you. A copy of Yeadons Register might help. By the time you are modelling they all seem to be using Ross pop safety valves. ( Pre war is a different minefield of variations. About 30 years ago I did the research and comissioned a scratch built 7mm J52 based on the ones on the E&WYURly. Whilst this would not quite meet the current expected level of super detailing it was a good representation. The safety valves are set into the tank top although how this would have worked in prototype practice isn't obvious.

Hopefully there is someone in possession of photos taken during the rebuilding of the preservation Ed and example.

Edited August 6, 2021 by doilum
Additional information

[Haddocksrock]

Thank you for that info. 

 

Looking at drawings for the J94 Austerity saddle tank that has the safety valves set on the boiler top in an oval recess in the saddle tank, which thinking about it, makes sense. If not the valves would have to have extension pipes thro the saddle tank water space? Makes me think the J52 would have a similar arrangement?

[watfordtmc]

I have the Yeadon's - all photos are taken from the side or track level....

 

There is one photo which shows an engine being scrapped, with the tank taken off.  The safety valves are mounted on to the boiler top, so they must have reached 'atmosphere' through an opening in the tank as you have surmised.

 

So the question is: did the J52's have a plate covering the opening or was it open to air as per the J94.

 

My own feeling on the matter, is that before the Ross pops, whatever safety valve was fitted had a covering; originally what Yeadon describes as a 'brass trumpet', and later a, cast iron casing.  Both trumpet and casing would have covered the void in the tank.

 

The Ross pops were fitted from 1926, and I reckon at that time it would have been seen as good practice to fit a plate over the tank top void through which the safety valves protruded.  Although the LNER was far from wealthy, the 20's  and 30's were not the era of war time austerity or shortage of materials that informed the design of the J94.

 

But that's only my opinion.  The unknown factor is whether the 'covering' would have been omitted during the war and subsequently.  In practical terms I'd be inclined to leave well alone unless there was an absolute need to make an alteration.

 

Yeadon notes that all engines (boilers) were converted to Ross pops but doesn't say when that was achieved or when each engine was converted.

 

Reference

Yeadon's Register of LNER Locomotives, volume 46 Part A Classes J52, J53, J54, J55, J57 & GNR 19, Booklaw Publications 2008.

(Although the brainchild of W. Yeadon, no Author or Editor is actually identified in the book!)

 

Regards

TMc

07/08/2021