6023

I recognise that the draughting has had to be redesigned for the shorter chimney to fit the modern loading gauge; but how was the same issue dealt with on 6024?

 

Double chimney, different issue.

 

Sorry, same issue, except that the length diameter ratio of the single went to an unproductive 1.55 and that of the double,
which was already lower originally, resulted in a still perfect functional 2.26.
Kind regards
Jos Koopmans

 

I imagine the answer to this in the short term could have more to do with there being a TOC ho have the capacity to operate on vac brakes on the mainline rather than progress at Didcot!

 

Off topic for a moment, but I find this fascinating. Jos is the draughting expert, I'm not, but I've often thought that the very low double chimney on the re-draughted Counties, developed by Sam Ell at Swindon in the 50's, must have been for a reason. As we all know, the chimney was much lower than the safety valve cover which, to some people, looked odd. My impression is that the final form double chimney Counties steamed consistently and very well. Is it correct to assume that with a taller double chimney on the Counties (like the one on the double chimney Castles) they would not have steamed so well, possibly with too fierce a draught?

 

I hope they have a back up plan if there are no main line tours to be operated it would be a shame not to hire it out to another line or maybe arrange a swap with another gwr loco and example a manor from the SVR.

 

I do not know the details of the Counties chimneys, but for the completion of the momentum transfer from steam to the combustion products chimneys have to have a certain length, the longer the better. I am under the impression that Ell just wanted properly working solutions and not really exceptionally good ones which at the time must have cost more experimental effort. The overall result was quite satisfactory given the total amount of redraughted engines.
Kind regards
Jos Koopmans

 

Questions for Mr Koopmans. Would lowering the top of the chimney require its internal diameter to be reduced to maintain the 1 in 6 'exhaust' cone up from the blast-pipe? If not reduced could the vacuum in the smoke-box be affected by air being drawn down through the now 'oversize' internal diameter? Indeed, is the 1 in 6 cone of any relevance? Thank you.

 

Basically all the proper ratios should be maintained: distance orifice to chimney choke 6 (orif.)diameters, diameter choke to orifice diameter 2.85 and chimney length-diameter ratio not really below 2. This is different from Ell's 26". If the ratios have different values the productivity of the front-end just starts to deteriorate. These dimensional ratios lead to a cone of 1:6 to the top of the chimney, but this has to do with the physical design only. The flow just behaves differently and certainly does not have such a cone shape within the chimney.
Kind regards
Jos Koopmans

 

Another month has gone by with no reports on 6023. A steaming is now surely just around the corner. Does anyone know of any news and developments with this loco?

 

Looked as though she was in light steam at least at the Easter gala, behind the main shed.

Simon

 

Photos on Facebook of 6023 in steam and doing some test runs on the demo line at Didcot in the last day or so - at a guess yesterday evening looking at the sky in the photos. As I recall once the weighing and balancing was done the next job was to do some running to see how the draughting arrangements work - at which point they'll be another step closer to knowing if she's ready to go mainline.

 

I do wonder how the draughting can be tested effectively on a 1/5th mile stretch of track with 2 or maybe 3 coaches. Surely a move to a heritage railway and test runs with increasing loads and differing gradients will provide more useful data than running at Didcot?

 

Quite possibly a future step once they've checked everything is running fine as light engine. No point shifting it miles only to find something obvious needs tweaking.

To be fair even on that length you can set up a fair old racket from the chimney as you set off from the far end of the site (Oxford Road) so its not all gentle stuff.

 

My understanding is that the post cutdown problems were readily evident at Didcot. So if the revised arrangement doesn't work effectively on the Didcot stretch then there's not much point in shelling out all the extra money in an off site move is there!

 

Found this on YouTube:

 

A progress update has been posted on 6023's website: http://www.6023.co.uk/news/news.htm

Looks like she'll be in steam at the May gala.

 

Makes me almost blush!
Kind regards
Jos Koopmans

 

You'll be doing this like a Cheshire

If it performs well on the mainline!

 

Good news indeed! Well done to all involved, especially Jos!