RMweb Gold RedgateModels Posted February 16, 2021 RMweb Gold Share Posted February 16, 2021 Bit of an odd question, but bear with me ... I'm frankensteining a 9F tank engine and would like to work out a theoretical water capacity for it. I've used 80xxx tanks as a basis, and know they were 2000 gal, but to guestimate how much I have increased the capacity by I need to know what they looked like under the pretty bodywork. Were they basically rectangular and did not drop below running plate at all? The bunker tanks again are a conundrum, did they just run to the sides or also run under the coal space? All this to get a custom plate made for the back of the bunker ........ Link to post Share on other sites More sharing options...
Wickham Green too Posted February 16, 2021 Share Posted February 16, 2021 I think the tin was what it said on the tin - just a huge irregular shape with no illusions ................ and obviously a real pig to calculate the volume - best of luck ! Link to post Share on other sites More sharing options...
JimC Posted February 17, 2021 Share Posted February 17, 2021 If all else fails could you work out the volume of the coal capacity from density of coal, and scale the size of the 80xxx tanks and extrapolate? Ought to get you in the region. And try hunting up some restoration in progress photos of BR standard tanks to get a feel for what shape the tanks were? Link to post Share on other sites More sharing options...
jointline Posted February 17, 2021 Share Posted February 17, 2021 And be sure to post some pictures when it's finished! Sounds fascinating! Link to post Share on other sites More sharing options...
RMweb Gold RedgateModels Posted February 17, 2021 Author RMweb Gold Share Posted February 17, 2021 47 minutes ago, jointline said: And be sure to post some pictures when it's finished! Sounds fascinating! Link to post Share on other sites More sharing options...
Gibbo675 Posted February 17, 2021 Share Posted February 17, 2021 Hi Redgate, Just to complicate matters the standard class 4 tanks had a huge void in the corners underneath the bunker. It can be made out on some weight diagrams but not others Gibbo Link to post Share on other sites More sharing options...
RMweb Premium Michael Edge Posted February 18, 2021 RMweb Premium Share Posted February 18, 2021 On 16/02/2021 at 15:28, RedgateModels said: Bit of an odd question, but bear with me ... I'm frankensteining a 9F tank engine and would like to work out a theoretical water capacity for it. I've used 80xxx tanks as a basis, and know they were 2000 gal, but to guestimate how much I have increased the capacity by I need to know what they looked like under the pretty bodywork. Were they basically rectangular and did not drop below running plate at all? If you look at their predecessors, the Fairburn version of the LMS 2-6-4T, you will find that the last ones have a rivet pattern along the bottom which follows similar lines as the BR 4MT. These are rectangular on the outside but the rivets show where the bottom is - The BR tanks are welded so you can't easily see. 1 Link to post Share on other sites More sharing options...
LMS2968 Posted February 18, 2021 Share Posted February 18, 2021 12 hours ago, Gibbo675 said: Hi Redgate, Just to complicate matters the standard class 4 tanks had a huge void in the corners underneath the bunker. It can be made out on some weight diagrams but not others Gibbo Aren't they the water spaces? 2 Link to post Share on other sites More sharing options...
Gibbo675 Posted February 18, 2021 Share Posted February 18, 2021 42 minutes ago, LMS2968 said: Aren't they the water spaces? Hi LMS, There is a tank under there but is not quite the shape you would expect and there are voids within the volume you may assume to be filled with water. It is that long since I was last under one I cannot remember to describe it properly of draw a diagram. I can tell you that the side tanks are quite a complicated shape on the driver's side compared to the fireman's side with cut outs and stepped shapes to accommodate the reverser, the fireman's side simply having the shape of the cab front and floor defining the outline of the tanks. The shape of the coal bunker slopes down from the shovelling plate and then upwards to the rear of the bunker at a similar slope to that of the tender with steeply sloped sides from the level of the inset raves, again as the shape of the tender. it is my guess that the voids are to do with balancing and weight distribution when running full. Gibbo. 1 Link to post Share on other sites More sharing options...
JimC Posted February 18, 2021 Share Posted February 18, 2021 Well, if we have a documented existence of unused voids and welded tanks on other BR standard tanks then that's more or less a get out of gaol free for your purposes. You're at liberty to assume 'invisible' welded joins and voids exist without having to try and design a measured volume. Link to post Share on other sites More sharing options...
RMweb Gold RedgateModels Posted February 18, 2021 Author RMweb Gold Share Posted February 18, 2021 Thanks all, I thought this would be tricky. Given that the 80xxx capacity was 2000 gals I probably can't push the 9MT to more that say 2750, even 3000 would be a 50% increase which seems unlikely given the extent of the extensions I've added. 2500 might be more realistic... Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 18, 2021 Share Posted February 18, 2021 2 hours ago, RedgateModels said: Thanks all, I thought this would be tricky. Given that the 80xxx capacity was 2000 gals I probably can't push the 9MT to more that say 2750, even 3000 would be a 50% increase which seems unlikely given the extent of the extensions I've added. 2500 might be more realistic... You need to create a weight diagram Link to post Share on other sites More sharing options...
RMweb Gold RedgateModels Posted February 18, 2021 Author RMweb Gold Share Posted February 18, 2021 (edited) On 18/02/2021 at 14:44, PenrithBeacon said: You need to create a weight diagram Best I can do 😉 Although the bunker is a bit longer now I think Edited July 11, 2022 by RedgateModels 3 Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 18, 2021 Share Posted February 18, 2021 (edited) 55 minutes ago, RedgateModels said: Best I can do Although the bunker is a bit longer now I think Nice drawing, really nice drawing I'm not only wondering about axle weights, but also the ability of this machine to go around curves with that trailing truck. I think I'd arrange it to be a 2-8-4T with a Class 5 boiler and standard tanks and bunker. The Brighton 2-6-4T had its origins in an LMS design of ?1941? which wasn't implemented. The idea being to give universal use of a Class 4 tank engine as the then Fowler and Stanier designs were out of gauge for some lines, so replacing obsolete 4-4-0 and 0-6-0 designs being used for secondary services. The need for such an engine became urgent on the post war SR, so Brighton took standard BR components, added a few more, and modified the cylinders to clear the restricted loading gauge on some SR lines, and put them back together again. I wonder how your imaginative (and I mean that nicely) locomotive would cope Edited February 18, 2021 by PenrithBeacon 1 Link to post Share on other sites More sharing options...
Gibbo675 Posted February 18, 2021 Share Posted February 18, 2021 Hi Folks, This was my attempt at not straightening the track too much, I might finish it off one day: It is a 2-8-4-2, there is a booster truck under the cab and the tanks are German style to allow better access to the fire box stays should any stays break. I have built other crazy engines from Dapol 9F kits if any one wants a laugh let me know and I'll post photgraphs. Gibbo. 1 Link to post Share on other sites More sharing options...
Wickham Green too Posted February 18, 2021 Share Posted February 18, 2021 3 hours ago, PenrithBeacon said: ......... The Brighton 2-6-4T had its origins in an LMS design of ?1941? which wasn't implemented. ......... Wasn't the Brighton 2-6-4T ( a.k.a. 80000 tank ) little more than a Fairburn tank with the corners knocked off - i.e. basically an LMS design that was implemented. Link to post Share on other sites More sharing options...
LMS2968 Posted February 18, 2021 Share Posted February 18, 2021 There was a bit more to it than that as it had to be squeezed into a narrower loading gauge, which meant smaller cylinders but the boiler pressure raised to compensate, but basically, yes. Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 18, 2021 Share Posted February 18, 2021 2 hours ago, LMS2968 said: There was a bit more to it than that as it had to be squeezed into a narrower loading gauge, which meant smaller cylinders but the boiler pressure raised to compensate, but basically, yes. I too think there was a lot more to it than that. I said that the Brighton tank had its origins in an LMS concept that wasn't fulfilled but it wasn't the fulfillment of that concept. It was a totally different design. There were, generally, many differences between LMS locomotives and their BR counterparts and apart from the Class 2 engines, those differences meant that there were very few interchangeable components. I suspect that it would have been possible to develop the Fairburn into a design that could do what the BR4 could do but Riddle's concepts used a very different range of components to the LMS and he always insisted that new designs used as many of the BR range of components as possible with very few new components. In this he following in the footsteps of Webb, Aspinall and many others. Nothing new there. The BR4 was the culmination of a design process that actually started with Maunsell on the SECR around 1914. See Philip Atkin's article in LMS Review for the full story. Link to post Share on other sites More sharing options...
RMweb Premium Michael Edge Posted February 19, 2021 RMweb Premium Share Posted February 19, 2021 12 hours ago, Wickham Green too said: Wasn't the Brighton 2-6-4T ( a.k.a. 80000 tank ) little more than a Fairburn tank with the corners knocked off - i.e. basically an LMS design that was implemented. Yes, that was my point regarding the rivet pattern on the tanks, like some other BR standards they were just LMS designs altered a bit and given the "house style". Link to post Share on other sites More sharing options...
LMS2968 Posted February 19, 2021 Share Posted February 19, 2021 (edited) The 'developed from' theory is rather elastic: there is a theory that Stanier took existing designs and developed them by fitting his own taper boiler to the already designed frames, the Baby Scots turning out as Jubilees; the Horwich Crabs as his 2-6-0s. This is true for a given value of true, but I know the 2-6-0s quite well and there is almost nothing from a Horwich Crab that will fit 2968; even the frames are different, and not only in the cylinder position but even the number of cross stretchers, use of axle box guides rather than hornblocks, etc. The engine which was 'developed from' can be very different to that from that into which the development finished! Edited February 19, 2021 by LMS2968 1 Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 19, 2021 Share Posted February 19, 2021 2 hours ago, LMS2968 said: The 'developed from' theory is rather elastic: ... Engineering designers generally use what has become known as 'mind experiments' to pursue their developments. That is they take a concept, in this case the concept of the Class 4 2-6-4T as originally expounded by Maunsell, and move it on to produce something which is more appropriate to their day. This is what happened with the 2-6-4T but there is no guarantee that the final product will be better than others in the series; there seems to be a general view of those who drove these machines that the Fowler 2-6-4T was the best engine out of all of them. In the case of the the Stanier 2-6-0, he seems to have taken the concept of the mixed traffic 2-6-0 and turned it into an engine that was very different, and better, than all its predecessors. 1 Link to post Share on other sites More sharing options...
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