SSM GSR 800 / CIE B1a 4-6-0

[Horsetan]

This giant undertaking appeared on a notorious auction site a week or so back. Although I've admired @Weshty's magnum opus since he launched it a while ago (is it really 13 years!???), it wasn't a priority and, anyway, there have been loads of other distractions that were more urgent. When this one popped up, the description "Model Locomotive Kit" - that's all it said, I kid you not - was less than prepossessing. Only the auction photos made it clear what it was, and I started thinking that Maedb might be possible one day.....

After a dying seconds bid, it fell to me, coming in at about 80 Euros less than new.

For anyone thinking about having a stab at the last word in Irish steam, this is what you get for the money:

- loco and chassis etches:

- quite a lot of castings, turnings, a resin mould, and many sundries including more than a few types and diameter of wire.... For some bizarre reason there were also enough parts to make 2 sets (8, in other words) of sprung buffers

- 

- another two etches for the tender:

....and to cap it all, you get 20 A4 pages of densely-typed, illustrated instructions and parts lists. I've turned all that into a PDF so I'll not be stuck for a copy. You also get numberplates, but not the elaborate nameplates. All three class members' plate sets are available, ready-painted, from 247 Developments.

It should be clear from the preview photos that this is not, and can never be, a beginner's kit. There's just too much of it for that. You can see where @Weshtyput in the hard graft and quite likely burnt the candle at both ends to get his artwork just so. That said, he wasn't mad enough to go overboard, so some of the valve gear has been simplified - there are no forked joints or forked rods at all, whereas comparison with the real thing in Cultra will show loads of them. It will be my job to put as many of those forks back in as I dare... Likewise, the expansion links are a 2-layer box, instead of the triple box they should be. Helpfully, there are a number of very useful close-up photos of Maedb on Flickr which show exactly how all the motion lines up and where each forked rod and joint is.

The instructions, by the way, don't tell you what wheels you should obtain. It is assumed that either you have bought a "OO" wheel pack from SSM or, if you're going the full 21mm gauge, that you already know what wheels to use. For the record, the engine portion uses 3ft 9-spoke plain bogie wheels, and 6'7" 22-spoke drivers with the crankpin in line with the spoke. The spokes are quite heavily-flared into the hub. I haven't been able to determine what the correct crank throw measurement is for a B1a - the few drawings that I've seen don't hint at this at all. The nearest finescale P4 driver is Alan Gibson's N15/King Arthur wheel which is listed as being 6'6" but which otherwise seems to have 22 spokes and the crankpin in the right place.

And we'll need axles for 21mm gauge anyway, so that means a special order going to Ultrascale and a potential 8 month wait.

The question you have to ask yourself is: "Do I feel lucky?" ....Well, do ya....?

[popeye]

Good luck. 

[Galteemore]

Wonderful stuff. Look forward to you working your magic on it. But ‘the last word in Irish steam’? Now there’s a statement - the GN types might throw the VS at you, the NCC lads would point to the WT, and depending how one interprets the phrase, of course, the last word in Irish steam was what came over from Beyer Peacock in 51…. It is interesting to note that, for all the comments on the short life of the 800s, Maedb (and likely her sisters too- haven’t the book with me) herself actually had a longer working life than poor old 27’s 18 years! 

Edited July 26, 2022 by Galteemore

[Horsetan]

41 minutes ago, Galteemore said:

.... ‘the last word in Irish steam’? Now there’s a statement - the GN types might throw the VS at you…..and depending how one interprets the phrase, of course, the last word in Irish steam was what came over from Beyer Peacock in 51….....

Funny, though, that all three types were touched, in one way or another, by lack of money.

The B1a: coal shortages, then dieselisation and lack of work

The VS: the GNRI was insolvent by 1958

The BP 0-6-4T: designed for a railway that couldn't afford to take it on

 

Now, here's a Flickr view of some of those forked rods:

In particular, note the way the radius rod divides into two to pass through the 3-layer expansion link. Combining lever, crosshead drop link, and small end of the eccentric rod are all forked.

The valve spindle has its own rectangular mini-crosshead which itself is driven via a short forked link from the combining lever. You do wonder if the kit design will tolerate the addition of these refinements without jamming up.....but they're impossible not to see.

Wheel construction is another source of fascination: see how the tyres are retained by setscrews between the spokes. There's a glimpse of the leading crankpin and I can see how close its position is relative to the axle centre, meaning that the crank throw is quite short - so that might mean my suggested King Arthur wheel might not work properly as that one has a longer crank throw (the pin is further away from the axle centre) which would cause the crossheads to travel further.

There is a possible alternative wheel which could fit the bill: the LSWR T9; same diameter, same number of spokes, but a much shorter throw. I think we need to have a look....

[Galteemore]

Fascinating stuff, Ht. It’s only when you want to model something that you really begin to look at it properly and notice the intricacies. As a scratchbuilder, I find it intriguing to see what wheels we can end up using. The T9 seems worlds away from an 800! I ended up using Stanier Pacific 3’ bogie wheels on a Sligo tank’s rear end….

Edited July 26, 2022 by Galteemore

[Horsetan]

1 hour ago, Galteemore said:

... The T9 seems worlds away from an 800!….

In looks, yes. But T9 wheels might be an expedient solution to reduce the possibility of the motion jamming up. The only other way is to redrill the King Arthur wheel for a shorter throw, but you need a jig to do that properly....

The T9 has a throw of 9 inches, the King Arthur is more like 13/14". Here's a view of Ultrascale's King Arthur wheel:

^^ Note that this is the later Maunsell wheel with the crankpin between the spokes, but you can see the almost-but-not-quite shape of the hub and the crank. The rim is also reinforced, so the Maunsell wheel is not correct for a B1a.

The B1a throw is unknown at the moment, but may be between those two - maybe @KMCE's drawings might tell us the measurement if they become available. Unfortunately, the works drawing uploaded by @BosKonay years ago in Forum Resources is unreadable because it was a low resolution scan, so all the handwritten measurements on it instantly get pixellated when you try to zoom in.

I had a dig around and found a set of old Sharman P4 3ft 9-spokes. They are a plain wheel, so the bogie is catered for. Just need the axles.

Incidentally, the kit came with a Mashima 1430 motor and High Level packs to build an extended drivetrain. I can't stand worm gears, so a coreless 1624 RG4 with a proper bevel-and-spur drivetrain from my RG4 drawer is now the substitute.

Quote

Fascinating stuff, Ht. It’s only when you want to model something that you really begin to look at it properly and notice the intricacies.

...and once you've noticed them, you can't unsee 'em!

One thing I forgot to mention is that the kit has its own beam compensation system designed in if you want to use it. I'm hoping we can adapt something a bit different in the form of a continuous sprung beam, as explained by the Central London Area Group - the wheelbase is similar to the LMS Black 5 and BR Standard 5, so it shouldn't be difficult to work out the measurements for pivot points and so on. One advantage of CSB is that it is less cumbersome than traditional beams, but you may need to modify frame spacers to allow the spring wire to pass through.

Edited July 26, 2022 by Horsetan

[GSR 800]

1 hour ago, Horsetan said:

In looks, yes. But T9 wheels might be an expedient solution to reduce the possibility of the motion jamming up. The only other way is to redrill the King Arthur wheel for a shorter throw, but you need a jig to do that properly....

The T9 has a throw of 9 inches, the King Arthur is more like 13/14". Here's a view of Ultrascale's King Arthur wheel:

^^ Note that this is the later Maunsell wheel with the crankpin between the spokes, but you can see the almost-but-not-quite shape of the hub and the crank. The rim is also reinforced, so the Maunsell wheel is not correct for a B1a.

The B1a throw is unknown at the moment, but may be between those two - maybe @KMCE's drawings might tell us the measurement if they become available. Unfortunately, the works drawing uploaded by @BosKonay years ago in Forum Resources is unreadable because it was a low resolution scan, so all the handwritten measurements on it instantly get pixellated when you try to zoom in.

I had a dig around and found a set of old Sharman P4 3ft 9-spokes. They are a plain wheel, so the bogie is catered for. Just need the axles.

Incidentally, the kit came with a Mashima 1430 motor and High Level packs to build an extended drivetrain. I can't stand worm gears, so a coreless 1624 RG4 with a proper bevel-and-spur drivetrain from my RG4 drawer is now the substitute.

...and once you've noticed them, you can't unsee 'em!

Wonder what the throw of the likes of a GWR King would be? IIRC they have a solid spoke so unsuitable but still would be interesting to compare!

Those forked joints in 00 gauge would be a sight to see! Regarding the valve spindle 'crosshead', I think it would be a beneficial addition for performance if you can get it to work, the wire that replaces it on the kit allows for too much slop imo. It may require a scratch build of the valve guides though as they lack the lip to guide the head as on the prototype.

 

Edited July 26, 2022 by GSR 800

[Galteemore]

7 minutes ago, GSR 800 said:

Wonder what the throw of the likes of a GWR King would be? IIRC they have a solid spoke so unsuitable but still would be interesting to compare!

 

 

14”

[Horsetan]

1 hour ago, GSR 800 said:

Wonder what the throw of the likes of a GWR King would be? IIRC they have a solid spoke so unsuitable....

Not only webbed spokes, but also crankpin between the spoke.

This one is for 21mm gauge, not OO. The only contact I have with 16.5 these days is in HO.

The Scalefour Society's annual Scaleforum show is on at the end of September; the Alan Gibson trade stand usually attends, so there'll be a chance to compare the King Arthur and T9 wheels for suitability. Likewise 247 Developments will be there and hopefully will have a stock of the nameplates.

At this rate, I might have to build some 21mm test track.....

Edited July 26, 2022 by Horsetan

[murphaph]

Fantastic thread. Someday I want to tackle this kit in 21mm myself, once I have built up some experience.

[Horsetan]

5 hours ago, Horsetan said:

....the wheelbase is similar to the LMS Black 5 and BR Standard 5,...

The coupled wheelbase comes out as 7'3" x 8'6" (29mm x 34mm in 4mm scale)

[murrayec]

@Horsetan

According to the info I have gathered the crankpin throw is 356mm / 14'' as confirmed above, the wheels are 1917mm / 6'-3'' diameter and the crankpin is in line with a spoke. The coupled wheelbase is 2214mm / 7'-3'' x 2604mm / 8'-7''.

Alan Gibson Ref 4878S driver wheels are the closest, they are slightly larger at 6'-6'' but have the right amount spokes and 14'' crankpin throw, the crankpin is in line with a spoke, and one also get a 22.5mm long axle in the packet.

Eoin

 

Edited July 26, 2022 by murrayec

[Mayner]

Ultrascale may be a better option than Alan Gibson for P4 wheels as I understand that the Ultrascale wheel centers are molded rather than a press fit into the rims, Ultrascale also have a superior crankpin system with the crankpin bush recessed into the wheel center and a recessed pin for use behind slidebars on outside cylinder locos.

I usually remove and Loctite Alan Gibson wheel centers to the rims because I had problems with the rims on Gibson wheels separating from the centers while pressing the wheel sets on to the axle while using a GW models wheel press tool.

I had no problems with Gibson OO/EM profile driving wheels in service once the rims

Alan Gibson supplies an extended 1/8" axle with the Outside Crank sets AGW Part no 5000,5001,5002, I cut the axle to length and face off in the Unimat on 21mm locos but need to find a use for my collection of surplus outside cranks!

[GSR 800]

3 hours ago, murrayec said:

@Horsetan

According to the info I have gathered the crankpin throw is 356mm / 14'' as confirmed above, the wheels are 1917mm / 6'-3'' diameter and the crankpin is in line with a spoke. The coupled wheelbase is 2214mm / 7'-3'' x 2604mm / 8'-7''.

Alan Gibson Ref 4878S driver wheels are the closest, they are slightly larger at 6'-6'' but have the right amount spokes and 14'' crankpin throw, the crankpin is in line with a spoke, and one also get a 22.5mm long axle in the packet.

Eoin

 

so it is a longer throw, more akin to a king or king arthur (spokes and webbing incorrect as mentioned)?

And only 6'3? quite unusual, was always under the impression they were 6'6 or indeed 6'7.

[Horsetan]

11 hours ago, murrayec said:

@Horsetan

According to the info I have gathered the crankpin throw is 356mm / 14'' as confirmed above, the wheels are 1917mm / 6'-3'' diameter and the crankpin is in line with a spoke. The coupled wheelbase is 2214mm / 7'-3'' x 2604mm / 8'-7''.

Alan Gibson Ref 4878S driver wheels are the closest, they are slightly larger at 6'-6'' but have the right amount spokes and 14'' crankpin throw, the crankpin is in line with a spoke, and one also get a 22.5mm long axle in the packet.

Eoin

 

Interesting. Can the 6'3" diameter be verified? 

The only sources I have are Steam Index and the Clements & McMahon book, both of which state driver diameter was 6'7".

Also, if you look at a broadside photo of a B1a and run a ruler through the driving axle centres and forward, does the line set by the ruler touch the top of the bogie wheels? At 6'3", the radius / midpoint is 3'1½", which would almost touch the top of the bogie wheel tyre. At 6'7", mid point is 3'3½", which would show a gap....

See also @KMCE's section drawing:

I'd say the axle midpoint line sails way above the top of the bogie wheel tyre....so 6'7", I think.

Edited July 27, 2022 by Horsetan

[murrayec]

@Horsetan

Oops! yes 6'-7'' wheel diameter is correct;-

I refereed above to old notes I made many moons ago! I went back to my drawings this morning and checked it......

Eoin.

 

[Horsetan]

OK so, we're back in Urie N15 wheel territory again. 

[KMCE]

On 26/7/2022 at 10:21 AM, Horsetan said:

The B1a throw is unknown at the moment, but may be between those two - maybe @KMCE's drawings might tell us the measurement if they become available

The throw is 14" as the cylinder stoke is 28".  Wheel diameter is as Eoin noted 6'7", however I believe that to be a wear figure with a nominal 6'6" design diameter.

 

The series drawings I prepared may years ago have been scanned but are in pdf format, so not conducive to uploading here.  I can share copies of the drawings, and my notes of figured dimensions taken from the original drawing offline if that is of use.  The purpose of the drawings I made was to take layer information off the original drawing, and are on negative film - the intention is that they can be overlaid to get various levels of information out.  I suspect that the drawing seen by most (which you refer to) was also built up in this way, as when you examine the print in detail, you can see some lines not entirely matching up.

Let me know if this is of assistance.  I would caution that I am somewhat under the weather at the moment and my not be able to respond quickly to requests, but hopefully I should be able to make some progress.

 

Regards,

Ken

[Horsetan]

7 hours ago, KMCE said:

.....  I can share copies of the drawings, and my notes of figured dimensions taken from the original drawing offline if that is of use.  The purpose of the drawings I made was to take layer information off the original drawing, and are on negative film - the intention is that they can be overlaid to get various levels of information out.  I suspect that the drawing seen by most (which you refer to) was also built up in this way, as when you examine the print in detail, you can see some lines not entirely matching up.

Let me know if this is of assistance.  I would caution that I am somewhat under the weather at the moment and my not be able to respond quickly to requests, but hopefully I should be able to make some progress.

 

Regards,

Ken

Anything that sheds a bit of light is welcome 

[Horsetan]

On the fifth read-through of the instructions, one of the particular design points stands out:

- The kit bogie is designed to pivot from a direct link at the rear to a mainframe stretcher.

There are no provisions made for a central bogie pivot, or for the bogie frames to directly bear the weight of the mainframe. This is slightly different to the real thing, where the bogie frames and stretcher directly take the weight of the engine frames and only slide laterally to a limited extent, whilst the bogie axles themselves are allowed to rise and fall.

- I want to see if the kit bogie can be modified to act more like the real thing. That means trying to make room for a central pivot / slide, not a rear one. Helpfully, the kit has an "L"-shaped mainframe stretcher here which is in virtually the right place for mounting a centre pivot. The vertical part of that "L" could also double as the back end of the inside cylinder.

I messed about with a spreadsheet initial diagram for the continuous sprung beam (CSB). It is quite rough at the moment:

This is based on a model weight of 200 grams (I'm sure the completed engine tops out at a good bit more than that), with an estimated centre of gravity ahead of the front axle. With the known wheelbase of 29mm x 34mm , the CSB has provisional pivots / fulcrums set at 16mm ahead of the centre driving axle and 19.5mm behind it. The outer anchors are set at 14.5mm ahead of the leading axle, and 11mm behind it.

The spreadsheet which works all of this out calculates a theoretical weight distribution of 32.5% for front and middle axles, and 35% on the rear. The aim is to get each axle bearing 33.3% each, so the current working is just messing with settings.

Incidentally, anyone interested in messing with CSB suspension might find the spreadsheet tools useful.

Edited July 29, 2022 by Horsetan

[Mike 84C]

Sounds like the same design as used for the Bandon Tank. I made mine with a piece of lead between the axle and frames, it works well.  Only way I could see to improve it would be a longer link pivoting at both ends and/or a soft conical spring that used to come in the American Tyco loco kits.

  If the csb springing has 33.3% on each driving axle where is the weight for the bogie going to come from?  

[Horsetan]

34 minutes ago, Mike 84C said:

..... If the csb springing has 33.3% on each driving axle where is the weight for the bogie going to come from?  

This is the same question I'm asking. All of the worked examples concentrate on the driving wheelbase only and don't take the bogie into account

[Mike 84C]

I am not an expert or skilled scratch builder, already quite a few on IRM but I can only surmise the front bogie does not play a major role in supporting or steering the loco. Which is how my Bandon Tank works and it rarely derails, usually with a hamfisted driver at the controls.

From my point of view Horsetan you seem to be choosing a difficult pathway, best of luck and I would love to see your B1a running before I popmi clogs!   

[StevieB]

Any photos of your Bandon tank anywhere to hand?

Stephen

[Westcorkrailway]

or

2 of some of my favourite threads 

 

[Mayner]

12 hours ago, Horsetan said:

This is the same question I'm asking. All of the worked examples concentrate on the driving wheelbase only and don't take the bogie into account

Russ Elliot's CLAG section on Continuous Beam Suspension does not appear to recommend extending CBS to include bogies.

http://www.clag.org.uk/beam-annex3.html#should-CSBs-be-extended-to-include-bogies

Though Scalefour Digest 41 includes is a diagram showing CBS for a 4-6-0 Fig 76

http://www.clag.org.uk/41-0rev.html#section19

Transferring weight to the bogie as Fig 76 would make sense though it may be a matter of how much.

It may be a matter of experimentation when weighting and balancing the loco before final detailing stage.

Officially the 800 Class had a locomotive weight of 84 Tons 4cwt, adhesion weight of 63 tons and a max axle load  of 21 Tons (Clements & McMahon), to all intents and purposes the driving axles and bogie pivot carrying an equal weight.

[Horsetan]

Thanks to @KMCE, I now have a clear set of his drawings plus quite a lot of measurements; I now know that the lateral centreline of the inside cylinder is just 4ft in front of the centreline for the outside ones.

This shows that the front of the outside cylinders does coincide with the rear of the inside one, and would have made quite a strong rigid structure on the real thing with virtually no flexing in the frames in this area. 

[Niles]

Are we forgetting the infamous Turfburner?  or Ireland's first new build loco, the Difflin Lake Railway's 2003-built "Duchess of Dlfflin"? (hey, narrow gauge still counts in my book).

And if the RPSI W Class is successful they'll be yet another word... the dead never shut up it seems. 

Edited August 6, 2022 by Niles

[Niles]

On 26/7/2022 at 7:39 AM, Galteemore said:

Wonderful stuff. Look forward to you working your magic on it. But ‘the last word in Irish steam’? Now there’s a statement - the GN types might throw the VS at you, the NCC lads would point to the WT, and depending how one interprets the phrase, of course, the last word in Irish steam was what came over from Beyer Peacock in 51…. It is interesting to note that, for all the comments on the short life of the 800s, Maedb (and likely her sisters too- haven’t the book with me) herself actually had a longer working life than poor old 27’s 18 years! 

That's an interesting point I never thought of before, though possibly poor 802 beat 27 on the short working life thing... I maintain there's a parallel between the 800s and the non-pushpull 201s. Nothing essentially wrong with them, but came at the end of their motive power type's reign and never really got to fulfill their destinies.

Edited August 6, 2022 by Niles

[jhb171achill]

On 6/8/2022 at 4:52 PM, Niles said:

That's an interesting point I never thought of before, though possibly poor 802 beat 27 on the short working life thing... I maintain there's a parallel between the 800s and the non-pushpull 201s. Nothing essentially wrong with them, but came at the end of their motive power type's reign and never really got to fulfill their destinies.

A comparison between the 800 class and 201 diesels tends to remind me somehow of silk purses and cow's ears...........

[Horsetan]

On 6/8/2022 at 4:52 PM, Niles said:

.... there's a parallel between the 800s and the non-pushpull 201s. Nothing essentially wrong with them, but came at the end of their motive power type's reign and never really got to fulfill their destinies.

Thing is, could the non push-pull 201s have been upgraded to push-pull? And, if that were possible, is there actually enough work for them to do?

[Branchline121]

2 hours ago, Horsetan said:

Thing is, could the non push-pull 201s have been upgraded to push-pull? And, if that were possible, is there actually enough work for them to do?

I think I remember someone saying something about a bit of an ICR shortage, so the 201s probably would have work to do, but I think they'd require a whole new fleet of coaches as there's not enough Mk4s. Irish Rail are ordering more ICR carriages anyways so I don't think the 201s would be needed sadly.

[Horsetan]

A quick visit to the Alan Gibson Workshop stand at Scaleforum yielded these driving wheels - as close as we're ever going to get to the GSR 800 pattern. Correct number of spokes plus crankpin in line with spoke. 

I came away with what I thought were three sets of the things. Only when I got home did I find that two sets were a completely different wheel which had been shoved into the trade stand tray where the correct wheels were supposed to be. Much cursing .  They're going back to AGW by post and hopefully the right ones will come back.

Next job is to get the Irish back to back gauge out and measure the desired axle length so an axle order can go to Ultrascale. 

[Horsetan]

Now we have all the right wheels in the right order....

....so we can take a pair out and place either side of the Irish back-to-back gauge, then measure as close as we can across the wheel hubs:

....and 25.2mm is the axle measurement we can give to Ultrascale. The same measurement also applies to the axles for the bogie wheels. Now wait 8 months whilst the man there is making those.

Incidentally, Ultrascale axles have a rounded shoulder which makes them a bit easier to press into wheel hub bores. AGW axles are strictly right-angled at their ends, so need to be "right first time" when being pressed into a wheel. 

I can't remember what the tender wheel diameter is, or how many spokes they have.....

Edited October 6, 2022 by Horsetan

[Horsetan]

On 26/7/2022 at 12:13 PM, GSR 800 said:

... Regarding the valve spindle 'crosshead', I think it would be a beneficial addition for performance if you can get it to work, the wire that replaces it on the kit allows for too much slop imo. It may require a scratch build of the valve guides though as they lack the lip to guide the head as on the prototype.

I'm just after finding a possible answer to this. Very similar piston valve guides used to be available from Stelfox (now long gone) and were cast in brass for the ex-LNER K3 pattern.

These were supplied in a pack of 4. On the outside face, they appear correct, whilst the inside is not. The idea is to graft the outside faces from one pair of castings to form the inside faces of the other pair....

Edited March 28, 2023 by Horsetan