16mm scale "Linda"

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Trevor Thompson
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16mm scale "Linda"

Post by Trevor Thompson » Mon Nov 02, 2020 9:22 pm

I have been building this for about 18 months.

It is based on drawings which Keith Bucklitch kindly placed on the steam model builders group files. While the original design was for slip eccentric he also provided a drawing for Stephenson valve gear - and that was why I built it. I couldn't get the valve gear to work as drawn - but I have now got it working after making some modifications.:
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The red and green lights are the electronic water gauge which so far seems far superior to the usual glass water gauge.

and finally a link to video of its first test run in the workshop:

https://www.dropbox.com/s/kzn4y7leac3bj ... 9.m4v?dl=0

It isn't finished but getting it to run feels like a major milestone!

Trevor

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Re: 16mm scale "Linda"

Post by steamgeorge » Tue Nov 03, 2020 10:37 am

Very impressive :thumbright:

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Re: 16mm scale "Linda"

Post by bambuko » Tue Nov 03, 2020 2:19 pm

Excellent Trevor :thumbright:
Wanted to have a look at the drawings, but the only one listed in "steammodelloco 16mm" group is "Charles"- Penrhyn Quarry ' main line' loco Charles.
Looks very much like your loco... (apart from the lack of tender and no drawing of alternative Stephenson valve gear).
What changes did you have to make to valve gear, to make it work?
Would you mind sharing some more details, please?
Electronic water gauge seems good idea, but I hope it will not be constantly flickering like it did in your movie :mrgreen:

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Re: 16mm scale "Linda"

Post by Trevor Thompson » Wed Nov 04, 2020 8:38 pm

Yes the drawings are actually for Charles. I worked out the significant differences between the locos and made the relevant changes.

I also have quite a few of my own photos of Linda - and there is quite a lot of information on various websites about the differences. If I remember correctly two of the three locos are very similar - and I think it is Blanch which is later and significantly different (piston valves). The cab spectacles caught me out though - and I had to change the spectacle plate.

The electronic water gauge is in the files section of the steam loco builders website. I have a cover to go over the tender which will have coal stuck on it. That should tone down the red and green lights ( which I plan to be visible between the lumps of coal. They have to be bright apparently to be seen in bright sunlight. The flashing is quite interesting - it is caused by the water in the boiler surging back and for as the loco moves. I find it quite reassuring to see that there is actually water sloshing about. The 3 d printed inserts in the tender are described in my thread on 3 d printing for 16mm garden railways in the general section.

As for the stephenson valve gear. Someone on the steam model construction group asked about stephenson valve gear - and Keith responded with a drawing. You would have to search for that to see what was described etc.

As to what I changed - well I changed most of it really. I could not get it to work as drawn so I went back to the books and simulators I have for valve gear design. The first thing I learnt was that the Stephenson valve gear has to be robustly built and well supported against sideways movement. Secondly I had to adjust the dimensions to get sufficient valve travel. And recently I had to dismantle quite a bit to get at the cranks and pivots which transmit the valve motion from inside to outside. I was losing the valve settings - because the arms were moving on the shafts. I have now pinned all four of these joints with 0.9mm brass wire.

The video was its first run - and it was going a bit fast for my taste. However now it has had a few runs I am able to control it better and it is running nice and slowly - and I won't need any form of flywheel device. The only issue left is that the valve gear is a bit stiff going from ahead to astern, and I am sure that will run in in time.
IMG_1013.jpg
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A photo of the underneath to show the valve gear. If I was making this again I would suspend the expansion links from both sides - its stiffer that way. And I used the valve cam followers in the slip eccentric drawings. I wouldn't do that again - I would make split ones like car connecting rods in future.

And photos of the loco as it is at the moment:

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If you want me to measure the various valve gear components and add sufficient information so you can copy the valve gear let me know.

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Re: 16mm scale "Linda"

Post by bambuko » Thu Nov 05, 2020 7:59 am

Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm Yes the drawings are actually for Charles. ...
I also did a bit of interweb searching and found family connection between Charles, Linda and Blanche :)
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...If I remember correctly two of the three locos are very similar..
Yes, the two that ended up at Ffestiniog (Blanche and Linda) are very similar, with Charles left in it's original condition as a static museum display.
This btw raises an interesting point - since your Linda reflects Ffestiniog modified state (with tender) should it also have a pony truck added?
I think (looking at your photos) it would be easy to add (you have frame spreader there ready to secure the truck to) and it might benefit loco handling?
I agree with you, that of the three locos, Linda seems natural choice for 16mm scale. Blanche with piston valves modification would not be ideal and Charles in it's original condition as a saddle tank loco without tender would miss all the space you have available in the tender :thumbright:
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...The electronic water gauge is in the files section of the steam loco builders website...
Yes, have a copy :thumbleft:
It is a great idea.

Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...The flashing is quite interesting - it is caused by the water in the boiler surging back and for as the loco moves...
I guess it is no different to water going up and down the water gauge (making reading of the level not easy)
At least with electronic gauge, you are missing capillary effect causing problems with small diameter water gauge glass.
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...Someone on the steam model construction group asked about stephenson valve gear - and Keith responded with a drawing...
Yes, it was an attachment to his email, long since lost in transfers from Yahoo to groups.io
No matter though - I am more interested in what you have done :D
Thank you for the attached "underneath" photo and details of your mods.
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...The video was its first run - and it was going a bit fast for my taste...
Yes, I did enjoy it much more running your video at half speed :mrgreen:
More difficult to achieve it in real life though...
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm... I won't need any form of flywheel device...
Good to hear it, because there is not a lot of space for one of this, particularly in a loco with inside full Stephenson valve gear.
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...If I was making this again I would suspend the expansion links from both sides...
That would follow full size practice :thumbup:
I guess these guys knew what they were doing when designing their locos :mrgreen:
Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...I used the valve cam followers in the slip eccentric drawings. I wouldn't do that again - I would make split ones like car connecting rods in future...
Are you talking about what K.B. calls "rocker assembly" on his drawing?

Trevor Thompson wrote: Wed Nov 04, 2020 8:38 pm...If you want me to measure the various valve gear components and add sufficient information so you can copy the valve gear let me know...
It would be useful not just for me but for anyone else attempting full Stephenson gear in 16mm scale, so I would be most grateful if you would be willing to share.
I know there is also a model of Blanche (with slide valve and full Stephenson gear) based on DJB Engineering - you can see some of it here:
https://youtu.be/PJGQ1jKTCYw?t=404

You can see also in this vid, how much better/easier is your arrangement with tender :)

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Re: 16mm scale "Linda"

Post by TonyW » Thu Nov 05, 2020 11:14 am

A lovely model, and some impressive work has gone in to it. Well done!
bambuko wrote: Thu Nov 05, 2020 7:59 am Yes, the two that ended up at Ffestiniog (Blanche and Linda) are very similar, with Charles left in it's original condition as a static museum display.
Similar certainly, but they hide their many and varied differences well. They are quite different machines to drive. Blanche is faster, but Linda is more powerful ... all down to the valve types. As for looks, the cab sides and tenders are very different.
bambuko wrote: Thu Nov 05, 2020 7:59 am This btw raises an interesting point - since your Linda reflects Ffestiniog modified state (with tender) should it also have a pony truck added?
I think (looking at your photos) it would be easy to add (you have frame spreader there ready to secure the truck to) and it might benefit loco handling?
That would, I believe, be a first for a 16mm Linda or Blanche. The full-size locos ran without a front pony truck until the early 1970s. Fitting of the pony trucks also involved extending the main frames forward about 8 inches. The truck swings between the frames. The tightest curve on the FR main line is Tyler's which, with a radius of 157 feet, works at about 2.5m radius in 16mm/foot scale and larger than the average curve found on most 16mm lines.
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Re: 16mm scale "Linda"

Post by bambuko » Thu Nov 05, 2020 2:03 pm

TonyW wrote: Thu Nov 05, 2020 11:14 am ...Similar certainly, but they hide their many and varied differences well....As for looks, the cab sides and tenders are very different....
Thank you for the details.
Talking about looks, do you happen to know of any sources of GA kind of drawing for either Linda or Blanche?
TonyW wrote: Thu Nov 05, 2020 11:14 am...The truck swings between the frames...
I have missed that bit, thank you for pointing it out.
Now that I look at the photos closely it is indeed clear.
TonyW wrote: Thu Nov 05, 2020 11:14 am...works at about 2.5m radius in 16mm/foot scale and larger than the average curve found on most 16mm lines.
Yes, it would mean larger min radius,
but it would be no worse than three coupled 0-6-0 loco? and if anything slightly better since some side movement in the pony truck would help?
So not for everybody, but not too difficult either?

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Re: 16mm scale "Linda"

Post by TonyW » Thu Nov 05, 2020 2:17 pm

bambuko wrote: Thu Nov 05, 2020 2:03 pmTalking about looks, do you happen to know of any sources of GA kind of drawing for either Linda or Blanche?
Sorry, no.
bambuko wrote: Thu Nov 05, 2020 2:03 pmYes, it would mean larger min radius,
but it would be no worse than three coupled 0-6-0 loco? and if anything slightly better since some side movement in the pony truck would help?
So not for everybody, but not too difficult either?
A valid point about being the same as an 0-6-0. The issue is that, as far as I am aware, nobody has done it but you may well be correct. The best I have seen (on a Roundhouse loco) is extended frames and a dummy wheelset that does not rotate and sits slightly above the rails.
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Re: 16mm scale "Linda"

Post by Trevor Thompson » Thu Nov 05, 2020 8:19 pm

Wow! I never expected this thread to generate so much knowledgable response!

Let me respond to the various things which have been mentioned so far. and add some background information.

The Stephenson valve gear - I will draw it up and share it here - just give me a few days to draw it!

The pony truck. I was thinking about adding it - but I now realise that it isn't a good idea - my railway has minimum curves of 4 ft 6 inch but other tracks where I am likely to run it (lockdowns permitting) are significantly tighter. Now I have enough information to suggest that I would be better leaving well alone.

I understand the desire to obtain accurate drawings for Linda - and I have come to the conclusion that sometimes it is better to act on limited information than to waite for accuracy. The model of the station building at Tan - y bwlch I am describing on the 3 d printing thread is a good example. It won't be totally accurate but does that really matter? It will at least contribute to the backdrop for the rolling stock.

So back to Linda - I wasn't really trying to make an accurate model. I just wanted something which would work. As in actually run under steam. The deciding factor was the valve gear drawing. I don't really like the idea of slip eccentric valve gear. Purely because it seems "naff" to have to push it to make it go the other way. I know that it doesn't matter if you are going round and round a circular track - but when I joined a local group and tried to run on someone else track (which is a loop) I realised the value of radio control - and if you have that why cant you control direction as well as speed.

I aught to admit at this point that I have been trying to build locomotives to my own designs for almost 10 years and of course I haven't had total success. The problem is that I have been trying to run before I can walk - having built an "Idris" - I then wanted to make an ACCURATE version of the De Winton George Henry. It is almost complete and it almost works. Here it is:
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Of course before I had finished it I went to the National show and saw Garratts. I couldn't help it I wanted one:
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Of course that doesn't quite work either. It is coal fired with full walshaerts valve gear and it is a compound. I spent ages trying to get piston valves to work and eventually hid slide valves within the piston valve outline. Anyway the Weir pump I built to provide boiler feed water worked - but was unreliable. That is what is holding that one back. It is no good using a goodall valve to pump water into a coal fired boiler it just puts the fire out as the steam pressure drops!

So you can understand the desire to step back and make something which someone else had designed again.

Hence the interest in the drawings for Charles - and making it roughly correct for Linda. The tender (for a large gas tank) being the incentive to make it Linda. If I had tried to make it into Blanche I would have ended up trying to make piston valves!

So the end result is satisfying - I have successfully created working Stephenson valve gear - knowledge which will enable me to finish the model of the De Winton. But more importantly I have another working steam locomotive to add to the "Idris". And it does work. The burner lights easily (with a 6mm hole in the bottom of the smokebox) every time.

It raises steam effortlessly, and while the poker burner is noisy - at least I can tell if it goes out. The O ring gas valve (in the files section of the steam loco builders site) shuts off when it is closed. I could never get the metal to metal ones in all the drawings to actually shut off properly.

Those lights flash annoyingly but I can see how much water is actually in the boiler. It doesn't lose steam pressure significantly when I add water.

Of course I am really pleased to be able to control it properly with the radio control. The O ring regulator which I have designed uses a course thread and allows full steam flow in 90 degrees of travel yet with radio control can be shut down quickly and controlled precisely. I know others will disagree but it works for me! I will post updated vidio over the weekend. The SWW group of the 16mm association have a virtual meeting this weekend and I will be showing Linda running outside.

So really I was trying gain the skills to finish my other projects.

I think you will see more of them shortly.

Trevor

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Re: 16mm scale "Linda"

Post by Trevor Thompson » Thu Nov 05, 2020 8:34 pm

Oh and I forgot to mention that I have added a whistle and tank filler lid as well as a brass dome to Linda - more of that tomorrow!

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Re: 16mm scale "Linda"

Post by bambuko » Fri Nov 06, 2020 6:00 am

Trevor Thompson wrote: Thu Nov 05, 2020 8:19 pm ...I never expected this thread to generate so much knowledgable response!...
Hardly surprising :mrgreen: (at least to me)
There are few threads detailing succesful 16mm loco builds with full proper Stephenson gear.

Like yourself, I don't care much for slip eccentric ;) and prefer the idea of RC control with proper valve gear.
My projects are also taking forever :oops: (perhaps because they are too ambitious) so the idea of simpler, quicker to build and available to run loco appeals to me as well...

I enjoy reading your thread - this is the kind of stuff that makes this forum so valuable (to me).
Look forward to more of it :thumbright:
Trevor Thompson wrote: Thu Nov 05, 2020 8:19 pm ...The Stephenson valve gear - I will draw it up and share it here - just give me a few days to draw it!...
Big thank you again.
Did you use any of the available simulators to work it out?
I normally like Charlie Dockstader's
but none of his have a launch type link for a loco :oops:

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Re: 16mm scale "Linda"

Post by dewintondave » Fri Nov 06, 2020 6:43 am

Fantastic workmanship Trevor!
Best wishes,
Dave

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Re: 16mm scale "Linda"

Post by TonyW » Fri Nov 06, 2020 9:54 am

Trevor Thompson wrote: Thu Nov 05, 2020 8:19 pmIf I had tried to make it into Blanche I would have ended up trying to make piston valves!
Blanche had slide valves before the front pony truck was fitted. Oil-firing, piston valves and the pony truck all happened together in 1972.
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Re: 16mm scale "Linda"

Post by Trevor Thompson » Fri Nov 06, 2020 10:23 am

[/quote]
Blanche had slide valves before the front pony truck was fitted. Oil-firing, piston valves and the pony truck all happened together in 1972.
[/quote]

Ah! It is useful to have this sort of information. So if I were to settle on my model of Linda being before the pony truck was fitted, what livery would she have been painted in?

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Re: 16mm scale "Linda"

Post by bambuko » Fri Nov 06, 2020 10:53 am

https://www.festipedia.org.uk/wiki/Linda

and specifically you are looking at this photo:
https://www.festipedia.org.uk/w/images/ ... -08-63.jpg

not embedded here because of;
...It may not be used for any other purpose without explicit permission from the copyright holder...
and Blanche here:
https://www.festipedia.org.uk/wiki/Blanche

with original condition photo:
https://www.festipedia.org.uk/w/images/ ... 2-8-64.jpg

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Re: 16mm scale "Linda"

Post by TonyW » Fri Nov 06, 2020 11:37 am

Trevor Thompson wrote: Fri Nov 06, 2020 10:23 amSo if I were to settle on my model of Linda being before the pony truck was fitted, what livery would she have been painted in?
As bambuko has mentioned, they did both run in Penrhyn black but were soon repainted in standard (at that time) FR green with red lining and black edging. This is Linda in 1964: https://plumbloco.smugmug.com/Trains/No ... -wxCnbqp/A

For Linda the only variations away from this did not occur until the 1980s (blue) and 1990s (Penrhyn black). Blanche has always been green since being repainted in the early 1960s.
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Re: 16mm scale "Linda"

Post by Trevor Thompson » Fri Nov 06, 2020 1:40 pm

So I have a valid excuse to paint her black and use the original style of Penrhyn lining.

That suits me fine!

I am not sure I will weather her that much though - just leave it for using her to weather the paintwork!

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Re: 16mm scale "Linda"

Post by Trevor Thompson » Fri Nov 06, 2020 1:49 pm

So I have a valid reason for painting her in Penhryn colours. That is convenient since I have suitable black paint and I am sure I can find the right colours for the lining. Gray and blue I think?

The valve gear design software I have been using is Don Ashton's, which is accompanied by a book "design procedures for Walschaerts and Stevenson valve gears". It covers launch and locomotive variants.

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Re: 16mm scale "Linda"

Post by TonyW » Fri Nov 06, 2020 2:38 pm

Trevor Thompson wrote: Fri Nov 06, 2020 1:49 pmGray and blue I think?
Blue and red, and no lining on the tender. That didn't happen until 1997.

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Re: 16mm scale "Linda"

Post by bambuko » Fri Nov 06, 2020 4:25 pm

Trevor Thompson wrote: Fri Nov 06, 2020 1:49 pm ...since I have suitable black paint and I am sure I can find the right colours for the lining...
You could have her totally black with no lining as per this photo of the prototype:
https://flic.kr/p/9SMW7d
Trevor Thompson wrote: Fri Nov 06, 2020 1:49 pm ...The valve gear design software I have been using is Don Ashton's, which is accompanied by a book "design procedures for Walschaerts and Stevenson valve gears". It covers launch and locomotive variants.
Have the book and the spreadsheet/design software... never managed to fathom the spreadsheet and the book was hard work as well :oops:
Learned a lot from the book, but never truly mastered the subject (must be me - thick as a plank :thumbup: )

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