More Pre-Grouping Wagons in 4mm - the D299 appreciation thread.

[Compound2632]

2 hours ago, Miss Prism said:

I assume those solebars are 5" thick?

 

Now you touch on a curiosity. The solebars, headstocks, and middle bearers of both those frame designs were 11" x 4½". The 1887 Private Owners Wagon Specification, which as we've seen was drawn up by a committee of which Clayton was chair, and Clayton responsible for the preparation of the drawings, called for solebars, headstocks, and middle bearers 12" x 5" - dimensions the Midland was not to adopt until it started building 10 and 12 ton wagons in the 20th century.

 

 So the Private Owners might well complain that they were required to have wagons built to a higher standard than those the railway companies adopted for wagons supplied for the same traffic.

 

I noted in my little essay on S&DJR 8 ton open wagons posted a few days back that for contractor built wagons, the Midland Loco Dept specified 11" x 5" in 1882 and 11" x 4½" with an iron flitch plate in 1898.

 

[Grahams]

The underframe on a 5 inch gauge wagon has a job to do, pulling trains of maybe 100+ kg. Through steel drawgear with a central cage and spring takes the strain of the train with no big forces on the wagon structure. The buffing leaf springs work as full size. The design follows closely the Midland drawings. 

Edited October 28, 2023 by Grahams
Typo

[Compound2632]

10 hours ago, Grahams said:

The underframe on a 5 inch gauge wagon has a job to do, pulling trains of maybe 100+ kg. Through steel drawgear with a central cage and spring takes the strain of the train with no big forces on the wagon structure. The buffing leaf springs work as full size. The design follows closely the Midland drawings. 

 

With continuous drawgear, the frame is taking very little of the strain. It would be interesting to see how a 5" gauge model of non-contiuous drawgear would stand up. From my diagram, you can see that the middle bearers take most of the force, which is then transmitted via the solebars. The buffing springs are amidships - if they were at the ends, they would soon pull the headstocks out.

 

When and where was continuous drawgear first used for wagons? Was the Midland's use in 1882 particularly early or not?

[Chrisbr]

5 hours ago, Compound2632 said:

When and where was continuous drawgear first used for wagons? Was the Midland's use in 1882 particularly early or not?

 

Best I can find at present is a GWR bulb underframe drawing from June 1882 showing continuous drawgear, so similar period...

Edited October 28, 2023 by Chrisbr
spelling

[Grahams]

4 hours ago, Compound2632 said:

It would be interesting to see how a 5" gauge model of non-contiuous drawgear would stand up.

They don't stand up. They would work for some light shunting but on the main line with reasonable length trains, depending on the construction, the headstocks rip off or the wagon separates into other components. I believe some of the early printed wagons (not mine) used to pull in half. I was fortunate not to have any major issues with this on my wagons. 

The forces which cause the biggest trouble are generally those when the engine snatches the train on starting. 

A further interesting aspect is the bearing springing. Some hand-built wagons are built with each spring leaf made from spring steel. For wooden bodied wagons, this gives far too high a spring rate and there is little vertical movement of the axleboxes. The result is some poor riding. The ground level tracks can vary in quality and springing with adequate travel is essential for the wagons to stay on the track. My wagons have a 3D printed bearing spring with a spring steel top leaf which can be tuned for the weight of the wagon. 

Wooden wagons or fully 3D printed bodies are generally too light to run empty. The D305 whisky wagon has a 4mm thick steel floor so it does not need extra weight. 

[Compound2632]

8 minutes ago, Grahams said:

They don't stand up. They would work for some light shunting but on the main line with reasonable length trains, depending on the construction, the headstocks rip off or the wagon separates into other components. I believe some of the early printed wagons (not mine) used to pull in half. I was fortunate not to have any major issues with this on my wagons. 

The forces which cause the biggest trouble are generally those when the engine snatches the train on starting. 

A further interesting aspect is the bearing springing. Some hand-built wagons are built with each spring leaf made from spring steel. For wooden bodied wagons, this gives far too high a spring rate and there is little vertical movement of the axleboxes.

 

Illustrating that material properties don't scale! 

[billbedford]

On 27/10/2023 at 14:56, Compound2632 said:

Now you touch on a curiosity. The solebars, headstocks, and middle bearers of both those frame designs were 11" x 4½". The 1887 Private Owners Wagon Specification, which as we've seen was drawn up by a committee of which Clayton was chair, and Clayton responsible for the preparation of the drawings, called for solebars, headstocks, and middle bearers 12" x 5" - dimensions the Midland was not to adopt until it started building 10 and 12 ton wagons in the 20th century.

 

Were they like modern planed timber smaller than the nominal sizes? ie was 11"x 4.5" the actual size of 12"x 5" timber. 

[Compound2632]

7 minutes ago, billbedford said:

Were they like modern planed timber smaller than the nominal sizes? ie was 11"x 4.5" the actual size of 12"x 5" timber. 

 

These are the dimensions given on the drawings and (by scaling to other dimensions) correct as such. (I can't vouch for the S&DJR specifications, since I've not seen the drawings that went with them, if any survive, but it seems to me very unlikely that they would be nominal sizes.)

 

I had a quick look in LNWR Wagons Vol. 1: at Earlestown, 10½" x 4½" was the order of the day right through from the D1 one-plank wagons of the 1870s/80s to the 20th century D84 opens - but always with flitch plates.

Edited October 28, 2023 by Compound2632

[Grahams]

20 minutes ago, billbedford said:

 

Were they like modern planed timber smaller than the nominal sizes? ie was 11"x 4.5" the actual size of 12"x 5" timber. 

I'd say the sizes must have been to drawing, with a tolerance, but not half an inch, otherwise the wagon would not have fitted together and resulted in the overall dimensions drawn. 

The Midland changed to 12 x 5 for the later wagons.

[Compound2632]

4 minutes ago, Grahams said:

I'd say the sizes must have been to drawing, with a tolerance

 

Tolerances on drawings were unknown to the draughtsmen of the Derby Carriage & Wagon Drawing Office, or to draughtsmen generally at that time. (When did tolerances on engineering drawings become standard practice?) Presumably there was some system of inspection of dimensions in the timber drying sheds or at the sawmill.

 

Thus an important part of workshop engineering was fitting - getting the intolerant parts to go together.

Edited October 28, 2023 by Compound2632

[corneliuslundie]

I am pretty sure from such things as RCH drawings etc that the sizes were actual, not nominal.

Jonathan

[billbedford]

29 minutes ago, Grahams said:

I'd say the sizes must have been to drawing, with a tolerance, but not half an inch, otherwise the wagon would not have fitted together and resulted in the overall dimensions drawn. 

 

There was nothing structural fitted to the outer face of the solebars. Only the holes in the headstocks for fixing the solebars would have been out by a quarter of an inch. Since the headstocks and solebars were made from the same stack this may explain the odd 14' 11" overall length of MR wagons. 

[Compound2632]

1 minute ago, billbedford said:

There was nothing structural fitted to the outer face of the solebars. Only the holes in the headstocks for fixing the solebars would have been out by a quarter of an inch. Since the headstocks and solebars were made from the same stack this may explain the odd 14' 11" overall length of MR wagons. 

 

My research suggests that length came about a different way. Pretty much the first new wagon design of Clayton's tenure was an enlarged lowsided wagon (three-plank dropside), 15' 0" long over headstocks rather than the 13' 6" of Kirtley's time. These had sides of 9" x 2½" timber but ends that were just two planks, 3" thick - Drg. 10. (You've made a kit of these!) The internal length was 14' 6"; that was evidently the key dimension, since in the next revision of this design, Drg. 213 (also a kit of yours), that dimension was maintained but the end planks changed to three 2½" planks, with the solebars shortened by 1" to suit. That underframe design stuck and its overall dimensions were repeated when continuous drawgear was introduced with Drg. 550. 

[Compound2632]

I must be recovering from the stomach upset that finished off our northern jaunt as I've just painted black the ends of a BR-built SR-type CCT (Parkside PC47). Bought after our club layout's outing to the Blandford show, with a view to amplyfing the S&DJR vibe snuck into the layout's BR(W) setting with the aid of my BR-period Bachmann 1532 Class 0-4-4T and a couple of Hornby Period 3 non-corridors. Erlegh Quay is supposed to be somewhere on the Bristol Channel so an S&DJR incursion is not unreasonable. We have even started laying track on the "fourth board" that will depict the eponymous quay itself.

 

I have numerous tins of Humbrol 33 matt that have gone solid or are otherwise defective. For wagons, I'm currently using Revel 6 matt which is a good off-black but for this I wanted a proper black black. (The CCT in question was built in 1951-1955 and I've been referring to photos of the preserved example at the Bluebell, built in 1955, which is the date for the layout). Lurking in the bottom of the paint box was a tin of Humbrol 21 Gloss that may well not have been opened in twenty years - in excellent condition, spread and is drying well.

Edited October 28, 2023 by Compound2632

[Nile]

You need Revell 8 , 6 is Tar black which is ok for tyres or weathered black.

[MikeOxon]

12 hours ago, Compound2632 said:

When and where was continuous drawgear first used for wagons? Was the Midland's use in 1882 particularly early or not?

In Whishaw's 'The Railways of Great Britain and Ireland' published in 1842, Plate XI shows the undergear of various GWR (broad gauge) vehicles, including the 'traction apparatus':

 

 

If anyone can shed light on the circular structures within the 'traction apparatus' under the 1st Class, the Posting Carriage, and the Carriage Truck, I shall be interested - some early form of shock absorber?

 

Mike

[Compound2632]

31 minutes ago, MikeOxon said:

In Whishaw's 'The Railways of Great Britain and Ireland' published in 1842, Plate XI shows the undergear of various GWR (broad gauge) vehicles, including the 'traction apparatus':

 

I thought I'd seen that "traction apparatus" somewhere recently, but probably on your blog, Mike, so that doesn't really help!

 

I think in all these, the drawbar is anchored to the buffing spring, so the drawbar pull is transferred to the middle bearers - i.e. not continuous drawgear. The "plan of wagon" shows a completely unsprung drawbar, which I think remained the norm for dumb buffered wagons - not only PO wagons down to 1887 but also (for example) LNWR D12 timber trucks. However, Midland drawings 336 (March 1878) and 559 (June 1882) for the dumb-buffered short and long timber trucks show continuous drawgear (the former pre-dating Drg. 550) with a central cradle, but rather than the coil spring to one drawbar (as in my sketch posted above) has a cylinder - india-rubber I believe - providing ¾" compression.

[Compound2632]

Straw poll:

 

If I use the word "strapbolt" do people know what I mean? 

Edited November 2, 2023 by Compound2632

[corneliuslundie]

I could make a guess but it is not a term I am familiar with.

Possibly a bolt which attaches a knee or similar to the body side or chassis.

Jonathan

[magmouse]

2 hours ago, Compound2632 said:

If I use the word "strapbolt" do people know what I mean? 

 

I think I do - are we supposed to say, or does that spoil the poll?

 

Nick.

[magmouse]

On 28/10/2023 at 08:46, Compound2632 said:

When and where was continuous drawgear first used for wagons? Was the Midland's use in 1882 particularly early or not?

 

This drawing in Atkins, et al, (final edition) shows an 1883 GWR wagon with what appears to be a rod connecting the coupling hooks and the buffing springs at either end - or possibly connected around the springs? 

 

This drawing must be a re-draw of an original, so may be a bit confused.

 

 

Nick.

[Mikkel]

3 hours ago, Compound2632 said:

Straw poll:

 

If I use the word "strapbolt" do people know what I mean? 

 

That would depend on the context. In terms of railway wagons, I would assume the same as Jonathan.

 

The Marquis de Sade, however, might interpret it differently.

 

[Chas Levin]

4 hours ago, Compound2632 said:

Straw poll:

 

If I use the word "strapbolt" do people know what I mean? 

 

No...

 

38 minutes ago, Mikkel said:

The Marquis de Sade, however, might interpret it differently.

 

...and I'm now even more intrigued than I was when you first asked!

[MrWolf]

I know what a strap bolt is in my line of work, but it's probably something completely different on here!

[Compound2632]

12 hours ago, corneliuslundie said:

I could make a guess but it is not a term I am familiar with.

Possibly a bolt which attaches a knee or similar to the body side or chassis.

 

11 hours ago, magmouse said:

I think I do - are we supposed to say, or does that spoil the poll?

 

9 hours ago, Mikkel said:

That would depend on the context. In terms of railway wagons, I would assume the same as Jonathan.

 

8 hours ago, Chas Levin said:

No...

 

8 hours ago, MrWolf said:

I know what a strap bolt is in my line of work, but it's probably something completely different on here!

 

Thank you for your replies, which seem to be suggesting that the term is not commonly understood. Maybe I'm not using it correctly myself? Anyway, I think we have three strapbolts here, connecting the headstock of a wagon to the solebar, one on the outside and two on the inside, which two also serve to secure one side of the buffer guide:

 

 

[Crops from scan of Derby C&W Drg. 682, MRSC 88-D0052.]

 

They're hypogryphical pieces of wrought iron, head of a bolt, tail of a washer plate. 

 

Sometimes also found connecting the middle bearers to the solebars but in this particular wagon that function is performed by a pair of tie-rods parallel to each middle bearer.

 

Looks like I need to explain "strapbolt" if I'm giving a detailed written description of the construction of a wagon.