what is this valve

[yorkiespud]

Hi

Can anyone identify the valve fitted to the side of the smoke box in the attached photos.
box 1 is a NER Class B, Box 2 is an NER class F.

Somewhere in the back of my mind I think I have heard them referred to as snifting valves but that could be a figment of a vivid imagination.

Many Thanks

Mossy

[neilgow]

I think you will find it is part of the cylinder lubrication system. These can be found on many industrial s with non superheated and low pressure boilers.

Someone should be able to explain the more intricate details of their operation.

NG

[yorkiespud]

I got some good suggestions from people on the O gauge guild forum yes a snifting valve so looked it up and:

Snifting valves are simple one-way “check-valves” that allow clean air to be sucked into the cylinder in the event of negative pressure arising. These were commonly mounted on the side of the locomotive’s smokebox from where clean air could be drawn, thereby causing (undesirable) cooling of the cylinders. Furthermore, admitting air into the steamchests and cylinders can result in oxydation of lubricants and the formation of deleterious gums, as described on the Tribology page of this website. Snifting valves can also leak, with obvious detremental effects.

Mossy

[JASd17]

Why ask a question, when you are determined to find the wrong answer?

John

[yorkiespud]

Well it appears its actually a displacement lubricator, probably either a Roscoe or Furness type.
The blub like ending to the handrail is likely to be a blower valve operated by a rod running through the hand rail.
Information provided by a couple of gents over on the O Gauge Guild forum.

Thanks to everyone on helped identify it.

Mossy

[silverfox]

IIRC snifting valves were only fitted to locos with superheatm tracers
When the regulator was open they were 'cooled' by the saturated stem going through them, which in turn because the superheater tubes ran throuth thre larger of the fire tunes increased to temp efficiency of the boiler
When the regulator is closed no saturated steam is passing through the superheater and is it subjected to the full heat of the fire. The snifting valve is sited on the outlet' side of the regulator and is ( well in 5in live steam terms) a ball which when the reg is opened is pushed up against the valve and shuts it. it normally connects to the superheater header manifold by way of piping
When the regulator is closed the pressure is released and the ball drops under gravity and air is drawn thought the tubes keeping them cool and then onto the cylinders when the regulator opens and pushes the ball back up! all automatic and the driver need not worry.

Apologies if i am teaching people to suck eggs but a few on here may not be aware of its use and how it works
If you can stand near the front of an LNER loco ( esp the later built ones) before it departs when the reg is opened you should hear a PHFFFFT sound which is the snifting valve closing

[Eightpot]

Just a quibble about the above, but my recollection of N2s starting from my local station (Brookmans Park) was that the sound was more like 'thok' than 'pfutt'.

[silverfox]

Eightpot
i was referring to the N7 lol

Yes the sound of the clack closing was quite distinctive

When i was spending most of my dinner times at Wood Green instead of swotting! the layout from East to west was IIRC Up slow carriage? Up local Hertford P1 Up local Hatfield P2/3 Up Main P4 Down Main Down Hatfield P5 Dn Hertford P6 Dn 'Khyber pass'

As we approached from The underpass at Palace Gates $min run from school!! one of the lads could tell if a Pacific was on the Up Carriage line by the sound, A Sprint to the footbridge over the south of the station normally found A Thompson A2 easing slowly down. Back then we never gave it a second though, but now, what WAS it doing on that line? and it wasn't an isolated incident

[StevieG]

Regarding the lines of the layout through Wood Green station Eightpot, you've done an excellent job of describing the typical use of each, but in cae you're interested, their official names were : -
Up Goods - (it was also possible for trains from your 'Hertford' and 'Hatfield' lines to use this line),
Up Branch (or Up Enfield, depending which signal box the detail was from), P1 : (It was also possible for trains from your 'Hatfield' line to use this line),
Up Slow, P2/3,
Up Fast, P4, - (but often still referred to by old hands by its historical "Up Main" name)
Down Fast (no platform) - (but often still referred to by old hands by its historical "Down Main" name),
Down Slow No.1, P5 - (it was also possible for trains for the 'Hertford' direction to use this line),
Down Slow No.2, P6 - (it was also possible for trains for the 'Hatfield' direction to use this line),
Down Goods (to the 'Khyber Pass') - (it was also possible for trains for the 'Hertford' direction to use this line).

When you say about the A2 "... easing down ..." on your 'Up carriage' line, do you mean slowly travelling north ?
If yes, it may have come from Hornsey Carriage Sidings (don't ask me why) : It was possible to signal a move off either of the two Hornsey C.S. Up Reception Lines by the 'Coronation Shed', back along the Up Carriage line south of the station and continuing along the Up Goods through the station and into Bounds Green Carriage Sidings.

[silverfox]

Steve


Having got all the right parlance for up and down, i get a wrong description for the A2!! by easing down i meant it was going slowly but on the Up!!

When you mentioned that the Hertfords could use the Kyhber and the Hatfields could use the up Goods/Carriage whereabouts were the respective points for these movements. Can anyone put up a track diagram for that are north of the station?
I say that as one of our spotting perches was a small area that was off Palace Gates road. If you know the area head west over the road bridge on the north side Just after the road junction with the road up to the palace there was a small entrance that went round the back of the shops.This overlooked Bounds Green Depot and carried those, no longer seen. raised cable troughs that had concrete posts every three feet. The edge of this looked down onto the Khyber line and had a drop of about 20ft
One of the 'contests' we did was to step from post to post along this troughing and the turning around and going back along the length. I think a lad called David held the record of 30 trips before he lost his balance. Luckily we didn't lose any lads down there!
As the platform ends were very close to the bridge IIRC there couldn't have been much room for points before the bridge, and i am sure that the Hertford and the Kyhber were diverging straight after the bridge.
I Think there was a good track diagram of Wood Green in Part 1 of Peter Costers book on the GNR north from KX but that is somewhere in the loft ATM waiting for the bookshelves to be refitted

[StevieG]

"Having got all the right parlance for up and down, i get a wrong description for the A2!! by easing down i meant it was going slowly but on the Up!! ... "

I wouldn't say wrong at all silverfox. Just trying to be sure I understood your meaning. I'd say that your 'easing down' meaning is probably the more appropriate.

" ... When you mentioned that the Hertfords could use the Kyhber and the Hatfields could use the up Goods/Carriage whereabouts were the respective points for these movements. Can anyone put up a track diagram for that are north of the station? ... "

Firstly, just to be clear, in talking about 'Hatfield' and 'Hertford', I am referring to trains of any type to/from those directions.


I will try to attach here a photo of an ancient piece of my rough Feb. 1970 handywork from my 'yooft', regarding layout signalling and signal boxes as things were then, plus tracks already removed by that time added in pencil, which if you can zoom in to it will hopefully show the points about which you ask. - -

- - It is drawn as from the east side (i.e. with south to the left) and was geared to continuing along the Hertford line, hence some distortion to track alignments at the R/H end, including that 'artificial S-bend' in the main line leading to Wood Green Tunnel (top right) -
- Bridge Road overbridge (not shown) crossed the line just off the R/H end of the station platforms, immediately right of signals 53/52, 36/37, and 28 (top); and 'yellow' disc signal [8] (at bottom).