S7 scratch building

[wagonman]

On 26/09/2023 at 17:08, airnimal said:

  I asked if they had any sandwiches for vegetarians.  Take the meat out came the stony faced reply.  Thanks Easyjet.  

 

 

All too common response to vegetarians, still. One of the reasons I don't travel much any more.

[Johnson044]

9 hours ago, wagonman said:

 

All too common response to vegetarians, still. One of the reasons I don't travel much any more.

Very familiar! Reminds me of a charity cycle ride for MacMillan- Reims to Canterbury- we stopped overnight near St Omer, I think it was- the consensus of opinion was that Buffalo Grill was the preferred option- and as the token vegetarian I dined on- Les Frites!

 

[Johnson044]

... but my own fault for going to a meaty restaurant instead of being Johnnie-no-mates and eating more energy bars and bananas by myself.

 

[Simond]

I do hope you visited the brewery!

 

(the beer will be vegetarian, if not actually vegan!)

Edited September 28, 2023 by Simond

[Andy Hayter]

2 hours ago, Simond said:

I do hope you visited the brewery!

 

(the beer will be vegetarian, if not actually vegan!)

Are you sure?  Many clarifying agents are based on animal products and so the beers are not even vegetarian.

[Simond]

Well, maybe, though I think that isinglass is a thing of the past.

[airnimal]

On 27/09/2023 at 19:10, BlueLightning said:

 

I have one of these attached to my coupling hook, seeing as I am doing it in 4mm, I don't think it would be possible without the extra light!

 

https://www.amazon.co.uk/Diagnostic-Penlight-CAVN-Flashlight-Emergency/dp/B01HAXUHQ6/ref=sr_1_1_sspa

 

Gary

Thanks for the information on pen touches. I spent Thursday morning walking around the shops looking for one without success.  It appears that everyone now uses the internet to buy most non food items. 

For someone like myself who doesn't buy on the internet it can be a problem,  but my eldest daughter came to the rescue and ordered one for me.  So I modified one pen by heat shrinking the hook using the largest pieces of heat shrink in my toolbox.  

[BlueLightning]

Glad the information was helpful

 

35 minutes ago, airnimal said:

For someone like myself who doesn't buy on the internet it can be a problem

 

I problem I understand well, I try to buy online as little as possible, in fact the only reason I have my current job (Running a model shop) is because I know how important being able to buy things on the high street is. I originally volunteered to work there as it would have closed otherwise due to lack of staff.

 

Gary

Edited September 30, 2023 by BlueLightning

[airnimal]

Back in the workshop again and the start of the pair of L&Y bolster wagons.  The W-irons have already been made, so a start was made on the wagon themselves.  There isn't much to these wagons but it took me quite awhile to get the first one to the stage we have here. I think I need my eyes testing again plus

I think old age is taking its hold of me. I don't appear to have the accuracy I once had because I am having trouble marking everything out as well as cutting and drilling in the right place.

 

There may be a bit of movement on the house front because one person has been 3 times to view it and brought alone a builder with him to advise him on alterations that he would like. We also have several other people expressing an interest in it so with and luck there maybe light at the end of the tunnel. 

[airnimal]

The basic framework on this pair of bolster wagons is now complete,  so before I go any further I need to sort out the joining arrangements.  On the drawing there are a couple of cross hatch bars with pegs locating in holes in brackets underneath the the ends of both wagons. I am not sure if this is practical or feasible in model form but I will give it a  try and see how I get on.  I don't have any metal suitable in the correct size so I have soldered some scrap waste etch together that hopefully will be close enough. 

The brackets have been folded up from more scrap etch,  but this first lot are not nearly thick enough. 

One problem I can see is the need to be able to separate the wagons to paint them and rejoin them without to much fuss. 

[WFPettigrew]

1 hour ago, airnimal said:

On the drawing there are a couple of cross hatch bars with pegs locating in holes in brackets underneath the the ends of both wagons.

 

How does it (the prototype as much as the model) go round corners if those bars are fixed at both ends?  I have been puzzling over this since you first posted the drawing.  If the two metal bars were actually an angle (i.e. each one starts and ends on the same wagon) then with a pin where they overlap it would work, but the side elevations suggests that is not what is happening.  It would work if the pins were in slots, but that also does not appear to be the case. 

 

I also don't really see why, if they wanted a fixed linkage between the two wagons, that they didn't just have a dirty great piece of iron/steel as per drawgear running through underneath a wagon, etc.  Why not simpy put in a pivoted rod that runs longitudinally and centrally?

 

I must be missing something, but I don't know what it is... 

 

All the best

 

Neil 

[Northroader]

The bars are pinned, not fixed, at each end. This allows the two curved rubbing faces to maintain contact on a curve. If you had a central drawbar, I think you’d need to allow a gap when the wagons are in a straight line, or the faces would jam on a curve.

[WFPettigrew]

3 hours ago, Northroader said:

The bars are pinned, not fixed, at each end

Pinned into a slot, or pinned beyond some sort of catch?  There does seem to be the latter shown on the side elevation, but with the pin being in or behind the edge of the piece of metal.  But there is nothing on the plan view. 

 

Granted if there is some sort of pinning then yes it could corner - but with a bit of slack that would be needed. so yes there would have to be a gap between the wagons, and with lightly laden or unladen then that could be quite a snatch loading onto whatever is providing the restraint? 

 

I suppose in the real world the actual degree of curvature will be small, especially with such short wheelbase wagons.  But then, if that's the case, the drawbar's failing that you point out would be less of an issue?

 

Sorry, still confuddled... 

 

Maybe I should shut up and let Mike complete his wagon and he will then prove to me how it works!

[Simond]

Pinned, as in a hole in the chassis, and a hole in the bar end, and a pin through it, at each end of each bar.  There is no fixing between the bars where they cross.  No slack.

 

it’s an “anti-parallel” linkage.

 

https://en.wikipedia.org/wiki/Antiparallelogram

 

atb

Simon

[WFPettigrew]

58 minutes ago, Simond said:

it’s an “anti-parallel” linkage

Thank you, and now finally it makes sense, thanks to the animations on that link. 

 

Notably the section on gear design under applications.

 

Fascinating!!

 

 

[Compound2632]

It does seem rather complex for the application, given that the LNWR D13 timber truck pairs used a simple pinned link!

[magmouse]

1 hour ago, Compound2632 said:

It does seem rather complex for the application, given that the LNWR D13 timber truck pairs used a simple pinned link!

 

Yes, the same with the GWR Twin Mites. I wonder if this is designed to reduce/remove the change in spacing between the two bolsters? The bolsters can turn, so they stay parallel with each other when the wagons are on curved track, but to stop relative movement between the load and the bolster also requires the bolsters to stay the same distance apart. A simple link between the wagons doesn't do this. However, my ability to understand the ramifications of the anti-parallelogram geometry isn't enough to know if it is better in this regard.

 

Nick.

[Compound2632]

4 minutes ago, magmouse said:

A simple link between the wagons doesn't do this.

 

In the case of the LNWR D13, I think it did because it was a fixed link. There was the same curved bumper on the inner headstock as on this L&Y pair, with a link plate top and bottom secured by pins. As far as I can seen, the only play would be due to wear on the components.

[magmouse]

Is the centre of the arc of the curved bumper at the pivot point of the bolster? There is also the question of what happens on a reverse curve, when the longitudinal axes of the wagons are parallel but offset.

 

I am just speculating with all this, but there must have been some motivation for choosing this more complicated linkage, even though in the end the more basic mechanism was the one adopted by most companies and survived.

 

Nick

[WFPettigrew]

31 minutes ago, magmouse said:

to stop relative movement between the load and the bolster also requires the bolsters to stay the same distance apart

 

I think this will depend what is slung across the bolster.  20 tons of oak tree trunk or steel rails is not going to be going anywhere without significant provocation- which is why the idea of using a 3 link coupling or a screw link has some merit - if the track geometry does change the distance between the ends of the wagons, having a flexible linkage would allow the load to stay put on the bolsters without any force trying to slide it one way or the other. 

 

But if the load is relatively light - some deal planks well short of the maximum for the pair of wagons - then they are likely to be sliding around all over the place. 

 

I guess this is why bogie bolsters were invented...!

[WFPettigrew]

9 minutes ago, magmouse said:

curved bumper

 

Going back to the wiki article, it would appear that the curved ends would need to be part of an ellipse rather than a true radial curve. 

 

[magmouse]

34 minutes ago, WFPettigrew said:

I think this will depend what is slung across the bolster. 

Jim Russell’s GW Wagons Appendix has a collection of photos showing loads on multiple single bolsters that have gone rather wrong, often resulting in derailments. Clearly it was an issue that needed addressing.

 

37 minutes ago, WFPettigrew said:

I guess this is why bogie bolsters were invented...!

Quite so!

 

Nick.

[Compound2632]

1 hour ago, magmouse said:

Is the centre of the arc of the curved bumper at the pivot point of the bolster? There is also the question of what happens on a reverse curve, when the longitudinal axes of the wagons are parallel but offset.

 

In the L&Y design, it's a shallower curve than that; the centre of arc is somewhere about the drawplate at the outer end. On the LNWR D13, it's a tighter curve, with centre about half-way between bumper face and bolster pivot.

 

I mis-described the LNWR coupling design. The plates top and bottom were just guide / washer plates for the pins. The actual coupling was a thicker iron plate on the centre-line but still no play other then wear; the pins secured this to the fork in the end of the drawbar proper. In the dumb-buffer version, the other end of the drawbar was fixed to the middle bearer, with the same arrangement for the outer drawbar - i.e. no springing whatsoever. The later sprung-buffer version had the usual drawbar cradle with coil spring amidships, but still no provision for longitudinal movement at the inner coupling.

[airnimal]

Well this pair of wagons has generated more than the usual amount of discussions about my wagons. 

I made up the brackets that fit under the solebar's and made new crossbars from scrap etch. The first pair I made were slightly short when I came to fit them. In the end I used the brackets as a drilling jig to determine the exact length.  

The pins are just lengths of .9mm nickel wire with the ends soldered in some brass tube. I will cut them down to the correct lengths later and countersink the floor to made them flush. I am not sure what to do about the saftey chains just yet or if I have any suitable.  

I am happy to report that this pair appears to work well pushing it through my sole example of point work without any problems.  There is still a long way to go but I think I am on the right track. 

[Jol Wilkinson]

8 hours ago, WFPettigrew said:

 

I think this will depend what is slung across the bolster.  20 tons of oak tree trunk or steel rails is not going to be going anywhere without significant provocation- which is why the idea of using a 3 link coupling or a screw link has some merit - if the track geometry does change the distance between the ends of the wagons, having a flexible linkage would allow the load to stay put on the bolsters without any force trying to slide it one way or the other. 

 

But if the load is relatively light - some deal planks well short of the maximum for the pair of wagons - then they are likely to be sliding around all over the place. 

 

I guess this is why bogie bolsters were invented...!

 

It appears that open wagons were often used for carrying flat length of timber, usually overhanging one end.  The LNWR also produced the D14 Deal wagon for carrying flat planks, basically a long wheelbase flat wagon with chains and hooks to restrain the load.

 

Bolster wagons seem to be aimed more at carrying large round section timers such as tree trunks, as they often had pivoting bolsters with stanchions. The LNWR D12 and D13 had stanchions which included a hole to which the chain was attached, so that the bolster was securely attached to the timber and would rotate wit it..