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Post by suctionhose on Aug 28, 2021 22:44:37 GMT
The problem with coils springs is they need a dampener to arrest the bounce. On a loco with inclined cylinders, the load on each side of the driving axle changes with the inwards and outward strokes - a change in load = deflection of the spring = rocking.
I tried rubber blocks on my early engines. Very stable but not sufficiently flexible for rough track. When I changed to coil springs, adhesion and flexibility was improved but tendency to rock under heavy load conditions was a consequence.
I used shot peened die springs, which are very close to specification, and placed stiff springs on the first and third axles (3rd is driving) and a softer spring on the centre axle. The stiff springs provide 4 point supoort while the softer centre axle can ride out the humps and hollows.
Springs of defferent rates can carry the same load by compressing the lower rate spring further. For an 0-4-0, I'd recommend a very stiff spring for the driving axle -so the load fluctuations equate to small changes in deflection - and a softer spring for the leading axle to allow a wheel on one side to drop into a hole or rise over a hump.
You may have your stiff spring compressed by 10 or 15% of free length and the softer spring compressed 30% to carry equal axle loads. That's the best you can do unless you have a dampener element like a rubber or urethane block in there somewhere to compliment the spring. Leaf springs are the answer because the friction between leaves quickly cancels the tendency to bounce.
Hope these comments inspire a solution that you're happy with!
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Post by terrier060 on Aug 28, 2021 23:40:24 GMT
Many thanks Ross. Yes very helpful. I did wonder whether I could use two springs, one inside the other with the coils opposite phase? Would this have a dampening effect? Nick has a similar Hunslet, which you are aware has a lot of overhang front and back, the rear being heavier due to the large copper firebox. His springing seems to be different to mine and much stiffer, so that the loco does not bounce violently as mine does.
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Post by terrier060 on Sept 4, 2021 23:02:01 GMT
We hauled the public for 5 hours today, our first open day since the shutdown. The loco behaved flawlessly with plenty of power and boiler producing plenty of steam, except for a derailment which was caused by this soft springing. I am going to try some firmer springs as a stopgap, but the problem is basically due to bad design where the springs are too short, and too weak, are difficult to adjust and impossible to replace due to contraints on the length, diameter, and strength. Further the existing springs have got considerably weaker over the past year.
The nearest stronger spring just does not have sufficient travel, which is about 0.5 inches. I can get one rated at 83N/mm but it only has 0.375in travel with 5 active coils.
The Milner design is much superior, where there is ample space to experiment with springs of different lengths, diameters and wire diameters. They are also easy to get at and adjust. Sadly this means a boiler removal which is a big job and will have to be done over the winter.
Not looking forward to it as everything is so heavy!
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Post by terrier060 on Sept 4, 2021 23:02:35 GMT
PS. Will send some pictures.
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Post by terrier060 on Sept 17, 2021 22:22:30 GMT
Lovely sunny day today to teach my granddaughter about steam engines. On holiday from Sweden the family had a lovely day at the track and Elsa (nearly 6) helped start the fire with charcoal then oiled round and drove the engine with family abord, applying smooth vacuum brales down the gradient. Family day out Sept 2021 by ed cloutman, on Flickr
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Post by terrier060 on Sept 17, 2021 22:32:44 GMT
The strong springs have arrived, but chatting to Ian and Neil at the weekend I may have ordered the wrong ones. They suggest that weaker springs with longer travel may be better than stronger ones with less travel. I think they are probably right, but seeing as I have these now, I may try putting them in the rear axleboxes which are relatively easy to get at, and see what happens. I think the heavy copper firebox does tend to make the engine tail heavy.
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Post by suctionhose on Sept 17, 2021 23:57:41 GMT
That's a really lovely engine! Girls of that age enjoy "being allowed" and I find they are very good students - they listen and go carefully where the boys can think they know it all... I've always enjoyed giving kids a go. We sometimes have one on one steam ups at home with the traction engine for various kids in the neighbourhood.
Anyway, I think you'll find stiff springs on the driving axle more stable. Some Krauss 0-4-0's only had springs on the front axle with the driving axle solid. Hard riding brutes...!
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Post by Roger on Sept 18, 2021 6:53:42 GMT
What wonderful photos, a real treat for everyone!
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Post by terrier060 on Sept 18, 2021 8:31:12 GMT
Thanks both - yes it was a great day and the sun shone all day even though the forecast was for rain. Elsa has seen pictures of the engine and wanted to drive it. I have not seen them since before lockdown so it was quite emotional. Sorry the images were so large but I did them on the iPad late last night (a challenge in itself), so they came straight out of my phone. Amazing quality for a phone!
Thanks Ross for the advice. I forgot that being an 0-4-0 the driving axle is the rear one, so what you say makes sense. If that is the case, I may only need to change the rear springs. I noticed climbing the gradient the loco got into quite a rocking motion in sync with the beat. They say that you lose a lot of power on a mountain bike with front fork suspension, particularly if it is soft, so the same probably applies to the loco?
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Post by terrier060 on Oct 18, 2021 12:05:33 GMT
Very wet here today, in fact it is the first rain we have had in weeks. So I found this YouTube video which you might find interesting! It is a vintage railway film called "Mishap" made in 1958 (I would have been in Singapore in those days). Hope you like it. Ed
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Post by terrier060 on Oct 18, 2021 12:09:26 GMT
Also there are quite a few on the Eskdale and Rumney 15 inch lines where you get a view from the cab the whole distance of the line. The way the engine sways makes you wonder how it stays on the track!
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Post by Deleted on Oct 18, 2021 14:59:43 GMT
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uuu
Elder Statesman
your message here...
Posts: 2,808
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Post by uuu on Oct 18, 2021 15:05:54 GMT
This could be it: YouTubeWilf Edit - and this could be a cab-swaying one YouTube
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Post by Deleted on Oct 18, 2021 15:06:51 GMT
ah... you got it too Wilf..
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Post by terrier060 on Oct 18, 2021 16:22:58 GMT
Yes sorry Pete that's the one!
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Post by terrier060 on Oct 18, 2021 16:28:02 GMT
Yes Wilf, I never realised how many detonators they put on the rails. A bit of overkill compared with today! We'd all be in a mess if the satellittes went down!
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Post by terrier060 on Apr 23, 2022 18:55:21 GMT
I have resurrected this thread as it had got lost on page 7 of Chat. The main reason is that on page 57 I described the graduated vacuum barake lever and the associaled steam ejector. I thought some feedback might be useful now that the loco is in use passenger hauling, and it is coupled to a tender and driving truck that you can see above on this page. Both the tender and the truck are quite heavy even before loaded. The graduated vacuum brake lever and ejector work very well and going down our steep gradient you can apply the correct amount of braking by looking at the vacuum gauge. The lever is moved to it's mid-way position and moving it slightly fore and aft gives quite sensitive control which can be monitored on the vacuum gauge. Both tender and passeger car are braked and pull a good 15 inches of mercury.
The ongoing project now is modifying the Froud injector design for existing pipework on my Hunslet (see Hunslet thread) which I hope to adapt for the two injectors on the A1X version of the Terrier. Roger is helping me with this and I will pulish the results as I go along. Of course I may never suceed in getting one to work, but one can but try. Roger, bless him, is full of confidence that it will work - me a lot less so! I will show the first trial on the Hunslet thread. It starts to make the right noise but will not pick up cleanly, but Roger has made several suggestions.
Ed
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Post by terrier060 on May 16, 2022 22:46:07 GMT
The vacuum brake has been used for some weeks now, passenger hauling, and continues to perform well. The initial making of vacuum takes about 1/2 minute as there are three tanks to evacuate, one on the tender and two larger ones on the passenger trolley. Once this has been done, further operation of the brakes are quickly restored. The exhaust from the ejector goes immediately down to the ground via a short tube. I decided not to exhaust, as is more common, via the smokebox, because the boiler steams so freely that I hardly ever use any blower. It is left just cracked open to prevent blowback when I open the firehole door. Exhausting into the ashpan just makes dropping the fire more difficult and seemed unecessary.
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Post by terrier060 on May 26, 2022 0:01:47 GMT
Time to get the running boards on the Terrier so that I can finish the drain cock gear which runs along the underside of the running boards from the cab as a flat iron bar. The outer part is supported by a valance which I have made from1/2inx1/2in brass angle. These are supported at each end by being fixed to the buffer beams. They drop down at the ends making it very laborious and wasteful to make from solid, so I decided to make brass blocks at the ends and silver solder them to the brass angle. The shape seems complicated, but I can leave that to the Tormach. I have made them 10 thou proud so that I can machine them flush on the outside edge after soldering. Valance01 by ed cloutman, on Flickr Valance02 by ed cloutman, on Flickr
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Post by terrier060 on Jun 4, 2022 23:07:48 GMT
Sorry for the delay on the valances, but Fusion 360 have stopped their rapid moves so that it was taking 1/4 hour for the tool to start cutting when it used to take a few seconds. So I am having to learn some G-code and change the program to insert the rapid move sections and also the tool change sections. I am going to try out the changes tomorrow without a tool in the machine .....JUST IN CASE!! Then I can start cutting again. Ed
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