Discussion in 'Steam Traction' started by Foxhunter, Jan 30, 2018.
It would straighten out some of the curves too!
Absence of evidence isn't evidence of absence though. How would you verify that a thermic syphon had irrefutably saved a firebox? You can imagine a crew that got into a bit of a squeaky bum time with water level but nonetheless didn't drop a plug may have been in no hurry to report the fact when back on shed.
Out of idle curiosity: there are videos online now taken inside a boiler under steam showing the movement (and turbulence) of the water. At what point did that technology become available: I'm reckoning probably not before the 1950s, and then I suspect steam locomotive engineers probably wouldn't have been first in line. Presumably the sum total of knowledge of conditions inside a boiler in use for railway practice was by indirect means.
That throws up some very intersting questions. First off, with recent advances in thermodynamic computer modelling, assuming evidence from real-world internal imaging matches theory to date, then, could said modelling techniques prove or disprove the claims for thermic syphons with a suffuciently high level of confidence to validate boiler design?
I've always thought the principal downsides to thermic syphons are (a) the additional initial cost of production and (b) degradation due to the abrasive nature of particulates on the 'dry' side, most especially in the vicinity of the outer (rearward facing) curve inherent in their form.
The changes to gas (and particulate) flows, where a gas producing firebed is employed, are another factor I've only seen mentioned with regard to resultant temperatures, but given a more complete combustion cycle is claimed, is it reasonable to expect a marriage of GP fire grate and thermic syphons would reduce wastage in service?
Could anyone with practical knowledge of these devices in service please enlighten me?
Could not agree more Tom.
Interestingly, I have only been close to two plug dropping incidents (from the train not the loco I should add), one for which involved "City of Wells". Sometime in the mid '80s it was out on a test run from York on the Harrogate circle. At Leeds there were concerns about the injectors feeding properly, but it was decided to carry on to York. Having descended Micklefield bank, the water level was such at Church Fenton that the driver decided wisely that it was time to stop. Unwisely however, having made the decision to stop, he then decided that it would be best to stop within the protection of signals so put the brake in hard. With the boiler water snuggling up hard against the front tubeplate as he came to a stand there was no way that thermic syphons were going to save the day here. Fortunately there was no serious damage done to the firebox crown, indeed the pride of some very experienced steam crew suffered more than the firebox did, but you have to wonder if the syphons did in fact help to recirculate water over the crown sooner and more effectively than if they were not there. We'll never know the answer to that one and it was a long time ago now.
This is something I've wondered myself. Swindon allegedly fitted a glass plate to the firebox of a Manor in the 50's. This may well be one of 'those'stories, but it supposedly came from Ernie Nutty, who was pretty high up in the R&D team.
Thanks Peter very interesting
there was no way that thermic syphons were going to save the day here.....
Fortunately there was no serious damage done to the firebox crown.
What you have to remember here is that the firebox crown was only exposed long enough for the fuseable plugs to give way but fortunately not long enough for the crown itself to be compromised. Once the loco came to a stand the water which had all gone forward during deceleration soon found its way back over the crown. With both feeds on it was then possible to keep the crown covered while the fire was dumped.
Just a side note, but I thought the soft Scottish water was generally considered quite good for steel fireboxes, and the LMS despatched a small batch of Black 5s so equipped to Scotland for that very reason. I'm sure properly treated water would be better, and my impression is that thermic syphons where fitted are a particularly demanding part of a steel firebox. I think the Bulleids had to have the region where the syphon enters the throat plate redesigned very early on to make them last.
That would be enough projects to take the A1 Trust nearly to the end of the century. Anyone care to predict what main line running will look like by then?
I won’t be around then so it don’t think it really matters what I think
They were saying it wouldn’t be around by the end of the century back in the 80s
My knowledge of certain loco’s and the companies that built them is lacking in some areas, (I don’t have that much on the LNER) I thought it was a bit more of a reputable source than Wikipedia.
Any information you need about Class 37’s though if I don’t know, I might know someone who does!
This is not entirely correct. The V4s were not designed specifically for the highland line. They were tested and compared against locomotives in East Anglia which is where they would have likely been utilized.
They ended up in Scotland as a comparison for the K4s was possible and they were found to be faster on certain stretches but had lower adhesion than the K4s.
There was absolutely no likelihood of them being built in large numbers for the LNER without some drastic changes to the design's material specifications taking place. This is because the War Office would have queried the spec and the new design quite extensively.
It has been quite easy in railway history to point the finger at Edward Thompson for the V4s not being built in larger numbers, but the truth is that it is amazing they were allowed to be built in the first place, given the restrictions on some of the materials utilized and the wariness to build new locomotives outside of the agreed WD types and anything outstanding on the order books (e.g. V2s and O2s).
Read what I wrote again, I said; ‘ had the ear and Gresley’s death not intervened they would have been built in large numbers.’
Think the Steel firebox on one also had a bearing on them being sent to Scotland. and once accepted they could do work up there the other was sent to Join
Well, I wonder how Bulleid got away with building his Merchant Navies.
I don't know a lot about the V4s, but if they had steel fireboxes then Scotland was the place for them, not anywhere near London with its hard water. Note that the Stanier Class 5 4-6-0s with steel fireboxes, 44720-727 were all allocated to Scottish sheds or Kingmoor for the reason of soft water in the entire area.
Suppose they could call a P2 General lee with an electronic Dixie Horn...
' Straightenin' the Curves, Flattenin' the Hills' , someday the mointain might Gitt'em but the Law never will etc).
However General Lee was of his time and place and therefore a bit of a racist
No, they would not have been built in large numbers. Fundamentally Gresley never received authority for whole-scale replacement of classes throughout his time on the L.N.E.R. The nearest he got was the J38 and J39 classes which supplemented existing locomotives, not outright replaced life expired rolling stock.
Arguably "got away with it" by virtue of his Q1 and Pacifics having much simpler materials choices and more austerity thinking throughout.
This no doubt explains why most of Bulleid's 140 steel firebox Pacifics were London based at one time or another.
Separate names with a comma.