North Yorkshire Moors Railway General Discussion

FYI the 6th episode of the Yorkshire Steam Railway is on channel 5 at 8pm. Whilst I know there are those out there that'll find it toe curling, lets look on the bright side and hope it will generate some sort of donations to help keep the Moors running/afloat. Especially considering the year that not just the preserved railways and greater heritage sector has suffered due in no small way the the Covid 19 pandemic.

 

https://www.youtube.com/watch?fbcli...CXkuvhSDu3V9nI&v=kCrYSSyXFQU&feature=youtu.be

 

I came across this on youtube. I was interested in the bit where someone was centre popping (?) stay holes in the WC inner firebox. Piglet mentions the necessity of making sure they line up with the outer, which is a point which obviously occurs, but shed no light on how they do this. The outer seemed to have been drilled already, and one thought which occurred was that one could perhaps insert the inner firebox temporarily and mark through, although if that had been done, presumably there was no need for the centre popping of the inner? Any thoughts?

 

I asked the same question on the NYMR forum a while back, but I can't remember - or find!- what the answer was. How have others - e.g. the Bluebell with 34059 - dealt with the same issue, I wonder?

 

Perhaps they made a template using the old inner firebox.

 

Perhaps they had the original drawing and marked the work up from that.
Pat

 

I must admit that if I was doing this job I would have drilled one plate and used it to drill the second plate but I've never had to do it on a curved surface so I'm speaking from a position of practical ignorance. It's also not helped by the fact that the stays are not necessarily at right angles to both plates because the plates aren't parallel to each other. I suspect that, having drilled the outer wrapper, throatplate and backplate, the position of the perimeter stays on the inner box are carefully marked out and the intermediate stays are then marked out by interpolation. Boiler work is very much a black art.
The NYMR does have a set of drawings for the boiler.

 

The Grosmont Mpd Facebook page has a number of photos of the work on the boiler over the last year or so (search for Hartland and the relevant posts will come up) I believe that the inner fire box has been in the boiler a number of times to gain assurance on the relative positions of the inner and outer boxes. I believe that during the course of the overhaul it was found that the boiler does not conform precisely with the drawings.

https://www.facebook.com/groups/878824592263336/?ref=share

I appreciate this may not help everyone as you need to have an account to become a member of the group.

Sent from my PRA-LX1 using Tapatalk

 

I can't offer any practical experience either; I checked back through the Bluebell News reports for anything about it, but all I have is:

"Marking out and drilling of pilot holes for the stays is underway with approximately 2,200 stays being required." (Spring 2018). That work was carried out at South Devon, who delivered a complete firebox with pilot holes drilled for all the stays; they were then opened out to full size by our boilersmiths.

Marking out was "complete" by Summer 2018 (in practice, given editorial lead times, that means no later than about mid May);

Autumn 2018 the firebox was back at Sheffield Park;

Winter 2018 "Measuring work has been undertaken on No. 34059's boiler to determine the length of stays required and the first order for stays has been placed along with orders for the specialist drills, taps, and reamers required."

The latest position (as at mid November) is that the only stays remaining to be fitted are the flexible stays around the bottoms of the thermic syphons; and the crown stays around the tops of the syphons.

The photo was from late 2018 and shows the pilot holes as received from SDRE; the numbering is a scheme from our boilersmiths to determine how many of each stay is needed for order. (I think the first digit referred to a particular diameter; and the last two to a particular length).

I'm afraid none of that really answers the question - probably about time the BN loco report was written by someone who knew what they were talking about rather than by some jobbing hack!



Tom

 

Yes, could be. You would have to come up with a very confident datum point or points. While I suspect that boilers are more accurately made than the sledge hammer-like nature of the work suggests, it may be difficult in practice on such a complex shape to assume that you can simply measure from a datum and everything will be fine. It would be good to have a chance to sit down physically or virtually with a boiler expert as there are several issues which are intriguing to the layman apart from this e.g. how you rivet the backplate on once the inner firebox is inside (on a narrow box loco, where the inner flares out to be too wide to be inserted from underneath), whether monel stays are still used on boxes which used monel in BR days (according to Burrows & Wallace's paper on the Bulleid fireboxes monel replaced steel stays in the breaking zones) etc. Such a discussion would be worth paying for, perhaps as a way of raising funds for whatever project.

 

Piglet does mention that the marking out was done from the drawing.
Pat

 

Have a look at: https://static1.squarespace.com/static/59f1c5ec51a58457c01eaed0/t/5a12c81c24a694409fc31b71/1511180326529/HGR-B9023-Is01-Steel+Rivets+&+Riveting.pdf If you don't want to read the whole document, go to page 17. If the firebox is left loose once inserted and the foundation ring left out, the box can be moved sideways somewhat to give increased space for doing the job. Alternatively, you can use patch screws instead of rivets. Although this is non-preferred, it is often done.

 

On a Bulleid firebox the inner and outer are welded together via the foundation channel and at the firehole door though?

Tom

 

Thank you. I will read that with interest.

 

Yes for Light Pacifics. Merchant boilers have a conventional, rivetted foundation ring - at least 35005's boiler does.
Pat

 

Huochemi's interest was in how you riveted up conventional narrow fireboxes where te 'box has to be in place before the backhead is riveted on. Wide fireboxes don't have this problem and Bulleid welded seam 'boxes even less so, as they can be inserted from below.

 

Evening All,

I'm still putting my lockdown time to good use by adding some old video tapes to my new YouTube channel. The latest addition is a further instalment of my 1992 video shot on the NYMR and this is the link if anyone would like to have a look:



The earlier parts can be seen in the NYMR playlist if anybody missed them:

https://www.youtube.com/channel/UCNOfePlql5cjht-0CQbee7A/playlists

Hope they're of interest.

 

Would you be interested?

https://www.nymr.co.uk/paid-vacancy-plant-fitter-operator

 

"plant-fitter", so only keen gardeners need apply?

(Ok, I know where the door is!)

 

But not couch potatoes..........! Don't worry mdewell I'm a few steps behind you too.