RMweb Premium Michael Edge Posted February 9, 2012 RMweb Premium Share Posted February 9, 2012 Find a drawing first, I think these had Walschaerts gear, not the usual Stephenson. 1 Link to post Share on other sites More sharing options...
coachmann Posted February 9, 2012 Share Posted February 9, 2012 Walschaerts gear yes. 1 Link to post Share on other sites More sharing options...
Dave Holt Posted February 9, 2012 Share Posted February 9, 2012 Here's a drawing of the valve-gear Austin 70140.pdf Hope it helps. Regarding the RH injector - it was an exhaust injector. I've checked in my Gibson kit and find it is represented in a very, very basic form on the white metal pipe casting, as a sort of blob near the "S" bend. Brassmasters do a rather better representation of the LMS style exhaust injector in both white metal and brass, although I don't know if it's available as a spare part. Don't forget that the bottom of the smoke box isn't completely circular, but slightly flattened to clear the inside valve chests. Coachman pointed this out in his thread on the subject or to me, anyway! Dave. 2 Link to post Share on other sites More sharing options...
Michael Delamar Posted February 10, 2012 Author Share Posted February 10, 2012 thats brilliant thank you, yeah I know about the smokebox, the casting also needs a bit of rubbing down around the edges too as its a fraction too large. Link to post Share on other sites More sharing options...
coachmann Posted February 10, 2012 Share Posted February 10, 2012 This is why I replaced the exhaust injector pipe casting with brass rod but retained the front and back detailed whitemetal bits. This engine was one of those near misses with a good boiler and modern engine portion with long travel valves etc. Stimied by "standard" 4F axleboxes like the S&DJR 7F's and Beyer Garratts. The book on LMS Compounds I read recently said Anderson and his Midland colleages were not idiots. Really....? 3 Link to post Share on other sites More sharing options...
clecklewyke Posted February 10, 2012 Share Posted February 10, 2012 This engine was one of those near misses with a good boiler and modern engine portion with long travel valves etc. Stimied by "standard" 4F axleboxes like the S&DJR 7F's and Beyer Garratts. The book on LMS Compounds I read recently said Anderson and his Midland colleages were not idiots. Really....? I find it incredible that such an apparently trivial flaw was not rectified on so many Derby designs. Surely it would have not been difficult to put in better axleboxes. Gresley would never have stood for it! Nevertheless, the 7Fs remain one of my favorite designs, conjouring up images of long trains struggling over Standedge, so I have one, which I built from the Gibson kit. It was a superb performer - until I dropped it - hence no photos. It still has a rather bent front buffer beam - but maybe that's prototypical for an engine which does a lot of heavy freight work and is unloved by its crews? Ian Link to post Share on other sites More sharing options...
Horsetan Posted February 10, 2012 Share Posted February 10, 2012 (edited) .....The book on LMS Compounds I read recently said Anderson and his Midland colleages were not idiots. Really....? It may have been one of those instances of taking standardisation a bit too far, rather than engineering idiocy...... I find it incredible that such an apparently trivial flaw was not rectified on so many Derby designs. Surely it would have not been difficult to put in better axleboxes...... Real engineering is not quite like modelling. Whether you could fit "better axleboxes" into an inside-cylindered engine depends on your frame design / proportions, etc. Looking at the GA of the inside motion, it does look as though there wasn't a great deal of space on the driven axle. Remember that, years later, when Ivatt wanted to have roller bearings fitted to the Black 5s, he ended up having to extend the wheelbase (meaning new frames) in order to be able to fit them in. Edited February 10, 2012 by Horsetan Link to post Share on other sites More sharing options...
RMweb Premium Blandford1969 Posted February 10, 2012 RMweb Premium Share Posted February 10, 2012 This is coming along really nicely and the revised washouts look the part 1 Link to post Share on other sites More sharing options...
coachmann Posted February 10, 2012 Share Posted February 10, 2012 Building new frames might have been an option had not the top brass on the LMS replaced Andersons cronies and Fowler, and talked William Stanier into sorting out their locomotive affairs. I suppose it was to be expected that 'locos in progrss' would continue being built (Compounds, 2P 4-4-0's, 2-6-2Ts, 0-4-4T). His 8F put paid to any thoughts of sorting out the 'Austin Sevens'. Seeing as this is the third thread on 'Austin Seven 7F's in recent months, I hope this interest spreads to Bachmann and they see that such a model of beauty would sell equally as well as their other 8-coupled locos. There is something about big black freight engines! 1 Link to post Share on other sites More sharing options...
Dave Holt Posted February 10, 2012 Share Posted February 10, 2012 (edited) By coincidence, I'm reading Eric Langridge's(?) "Under 10 CME's - Vol 1" at the moment and he did a lot of the design work on these locos, including the valve gear layout, and has quite a bit to say about them. As Larry has said, excellent boiler (based on the LNWR G2a) and modern, long travel valve gear - let down by the axle boxes and crank pins inherited from the 4F. It's correct to say that where possible, standard parts were incorporated into new designs to minimise tooling and spares holding costs. EL explains that although the axleboxes were susequently criticised and proved to the the Achilles heal, space considerations made anything much better difficult in the space available - especially with Stephenson's gear requiring 4 eccentrics. One way to improve bearing area would have been to increase the journal diameter, but this would be non-standard and mean new box design, larger frame cut-outs and horn-guide castings - all adding cost and weight. In this case, the axle loadings were less than the 4F and the piston loads about the same, so the existing boxes and crank pins were thought to be adequate. I also suspect that, at the time the design was being done, the problems with the 4F's hadn't really started to become apparent. As Larry says, any thoughts of solving the problems with the Austin 7's were quashed by Stanier's 8F's and later by the influx of the gorgeous WD's!!!! Michael, if you do decide on inside valve gear (preferable working), perhaps you could get it etched and sell interested parties (like me!) a spare one to use in our Gibson kits? Dave. Edited February 10, 2012 by Dave Holt Link to post Share on other sites More sharing options...
clecklewyke Posted February 10, 2012 Share Posted February 10, 2012 (edited) Michael, if you do decide on inside valve gear (preferable working), perhaps you could get it etched and sell interested parties (like me!) a spare one to use in our Gibson kits? And me, please! If you offer it to Colin Seymour he might be interested in incorporating it in Gibson's kits Ian Edited February 10, 2012 by clecklewyke Link to post Share on other sites More sharing options...
Tony W Posted February 10, 2012 Share Posted February 10, 2012 And me please, and I'm sure someone else could be persuaded to purchase as well. Tony Link to post Share on other sites More sharing options...
Michael Delamar Posted February 10, 2012 Author Share Posted February 10, 2012 I havent really got the skill, knowhow or time to do that but if theres something off the shelve which is similar i think id go for that. quick shot taken today Link to post Share on other sites More sharing options...
Andy G Posted February 10, 2012 Share Posted February 10, 2012 And me please, and I'm sure someone else could be persuaded to purchase as well. Tony Yes he could be . Andy Link to post Share on other sites More sharing options...
coachmann Posted February 10, 2012 Share Posted February 10, 2012 Unless you are fitting working eccentrics, and itsa bit late for than now, I'm sure a few bits of metal painted mucky orangish-red would suffice to fill the gap up to the second axle. And of course those big balance weights. 1 Link to post Share on other sites More sharing options...
Michael Delamar Posted February 10, 2012 Author Share Posted February 10, 2012 That's what I was thinking to be honest, its only because there is. Such a visible gap under the boiler and between the frames, or if someone did some dummy valve gear for a 4f or similar was the other option Link to post Share on other sites More sharing options...
Michael Delamar Posted February 13, 2012 Author Share Posted February 13, 2012 just come across this nice prototype shot. http://www.flickr.com/photos/72213853@N03/6777503321/in/photostream Link to post Share on other sites More sharing options...
Michael Delamar Posted February 13, 2012 Author Share Posted February 13, 2012 and this one on the scrapline http://www.flickr.com/photos/64215236@N03/6820059413/ Link to post Share on other sites More sharing options...
coachmann Posted February 13, 2012 Share Posted February 13, 2012 The shot south of Parkbridge is probably the 12.10 Ashton Oldham Road - Oldham Glodwick Road goods. It was based at Lees from June 1951 until October 1957 where it was withdrawn. Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 14, 2012 Share Posted February 14, 2012 Re the discussion on axle boxes, it is worth pointing out that the GW and SR had inside cylinder engines with the same (or similar) size of cylinders which restricted the length of the axle journals. I suspect the real problem, and the solution, was that the MR and LMS used 'crown' lubrication for axles and not the 'underkeep' style which Stanier introduced to the railway. Stanier was told to change the 'crown' lubrication to 'underkeep' for the 'Royal Scots' and that class then had its problems solved, but this solution wasn't applied to the 'Austin 7' class, the more the pity. I share the view expressed earlier that minor changes to the 'Austin 7' would have improved the engine no end, but it has to be remembered that these were new engines at the time and the railway, like all businesses at the time, was under considerable financial stress and it might have been a financial issue as well as an engineering one to go back to the Accountant ask for more money at a time when the LMS was borrowing money at a discount. There is also the issue of the politics of the new man ie Stanier. Fowler's reputation had been pretty well shredded and I doubt if anybody who valued his career would have championed one of his designs and pointed out the obvious, ie a 7F with underkeep lubrication and Stanier 8F wheels would be a winner as a mineral slogger. To do so would have undermined the case for the 8F. Not a good career move! By way of parenthesis, it might be worth pointing out that Beames, whose upward mobility had been terminated by Stanier's arrival, applied underkeep lubrication to the various sub classes of LNWR 0-8-0 while rebuilding them to the G2a and this was a major reason for the success of the class in subsequent years. Regards 1 Link to post Share on other sites More sharing options...
RMweb Premium Blandford1969 Posted February 14, 2012 RMweb Premium Share Posted February 14, 2012 Thinking about doing valve gear for this engine, the GA gives alot of the details. The one thing you can't see is the motion support bracket, which I would assume was at the ends of the slide bars with extension pieces to then support the expansion links? Link to post Share on other sites More sharing options...
PenrithBeacon Posted February 17, 2012 Share Posted February 17, 2012 Not come across any working footage either unfortunately. I've just been viewing 'Decades of Steam 1920s' and there is a very short clip of one of these engines towards the end. I'd be surprised if the sound is authentic though. Regards 2 Link to post Share on other sites More sharing options...
Dave Holt Posted February 17, 2012 Share Posted February 17, 2012 Thinking about doing valve gear for this engine, the GA gives alot of the details. The one thing you can't see is the motion support bracket, which I would assume was at the ends of the slide bars with extension pieces to then support the expansion links? Here's, hopefully, a better image of the drawing. The motion bracket is a mainly horizontal plate (well, sloping to be parallel with the piston rod), with some up-standing ribs including at the rear end where the expansion link trunion supports are attached. At the front end, in plan, the motion plate extends forward roughly level with the front face of the lubricator. It's then cut away towards the loco centre line to clear the combination levers. Hope this helps. Dave. 2 Link to post Share on other sites More sharing options...
RMweb Premium Blandford1969 Posted February 18, 2012 RMweb Premium Share Posted February 18, 2012 Thanks Dave, I was begining to think from the original that's as it was and this confirms it. Duncan Link to post Share on other sites More sharing options...
Dave Holt Posted February 18, 2012 Share Posted February 18, 2012 Duncan, Yes, there's some surprising features on view for a basically Midland engine. In particular, the 3 bar slide bar and cross-head arrangement - based on Gresley Pacific, I believe, but also very similar the eventual BR Standard practice. The motion bracket looks incredibly flimsy with almost no vertical stiffness as even the rear vertical was cut away to clear the radius rods in their lower positions. If you do create a replica, I'd be most interested, as would several others, judging from previous responses. Sorry to Michael for hi-jacking his thread somewhat! Dave. 1 Link to post Share on other sites More sharing options...
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