Midland Railway in EM gauge

[Rowsley17D]

2 hours ago, DayReturn said:

I don't think I've seen the Jidenco frets for the Kirtley 0-4-4T but based on the Kirtley 2-4-0s and the 0-6-0, you may find some mysterious little strips of brass probably unnumbered and probably with holes or half-etched "rivets" etched in the ends for bolt heads,  16 in total, to make up these spring stays.  I won't comment on how to actually fit them if you find them!  The George Norton/LRM version has them lollypop shaped and has little half-etch grooves in the running plate to located them.

 

Now you mention it on the nickel silver etch there are two sets of two parallel strips 32mm long. They are just plain but I wonder if these are the spring stays/hangers?

 

To answer Stephen's @Compound2632 observation I was going to add the back hangers later as the super glue was not doing its job.

[DayReturn]

1 hour ago, Rowsley17D said:

 

Now you mention it on the nickel silver etch there are two sets of two parallel strips 32mm long. They are just plain but I wonder if these are the spring stays/hangers?

  32mm long? Nothing etched into them?  The coupled wheelbase is 32mm and platform width is ~32mm - maybe it's brake pull rods.  Stupid question, but they aren't the coupling rods are they?!  They may be arbitrary space fillers.  If all else fails, read the instructions . . . . Jidenco? . . . . umm, well maybe not :-)  !!

[Nick Holliday]

12 hours ago, DayReturn said:

  32mm long? Nothing etched into them?  The coupled wheelbase is 32mm and platform width is ~32mm - maybe it's brake pull rods.  Stupid question, but they aren't the coupling rods are they?!  They may be arbitrary space fillers.  If all else fails, read the instructions . . . . Jidenco? . . . . umm, well maybe not :-)  !!

For once, the Jidenco instructions do have the answer.  I suspect that the original design and production of this particular kit was carried out by someone else, and subsequently passed into the Jidenco stable.  The instructions are reasonably comprehensive, by their standards, and contain useful tips and suggestions which clearly show that the designer had built at least one of them himself, before letting it loose on the unsuspecting public. The bodywork is described in fair detail, and the brass etches have appropriate numbers to allow identification of most, if not all the body parts, although the chassis instructions rather revert to type, no numbering of parts, and the helpful "Assemble up brake detail sand boxes and rear pony truck." (There are six pieces in the brake gear, the pony truck appears to have just the sides and, what may be the sandbox is a plain rectangle of nickel silver - but there is a drawing, helpfully at reproduced at 1:68 scale!)

Back to the answer - In the body section it says "Glue or solder springs in position and using the strips found on the chassis fret make up and solder in position the springs and supports."

The white metal castings, such as the springs, and brass turnings look pretty good.

[Compound2632]

Ah well, I'm glad I had the nerve to raise the question!

[Regularity]

1 hour ago, Nick Holliday said:

helpfully at reproduced at 1:68 scale!

That's just typical. 

So many people want to model in S, but never quite make the transition...

Edited September 28, 2021 by Regularity

[Denbridge]

2 hours ago, Regularity said:

That's just typical. 

So many people want to model in S, but never quite make the transition...

Isn't S 1:64 though rather than 1:68 

[Compound2632]

2 minutes ago, Denbridge said:

Isn't S 1:64 though rather than 1:68 

 

I though Simon was referring to the proportion of people who think about modelling in S that actually take the plunge.

[Regularity]

19 minutes ago, Denbridge said:

Isn't S 1:64 though rather than 1:68 

 

16 minutes ago, Compound2632 said:

 

I though Simon was referring to the proportion of people who think about modelling in S that actually take the plunge.

My point is, that even that drawing wasn’t quite to 1:64, although closer than the 1:76.2 most people stick with…

 

[DayReturn]

10 hours ago, Nick Holliday said:

Back to the answer - In the body section it says "Glue or solder springs in position and using the strips found on the chassis fret make up and solder in position the springs and supports."

I am loath to mention this, but the 780-class, Dubs-built 0-4-4Ts had flush countersunk rivets on flared bunker sides and pairs of stays (spring hangers) that can be fabricated from the brass strip, whereas the 690-class Beyer-Peacock 0-4-4Ts had straight-up bunker sides, snap rivets as per your lovely model Mr Rowsley,  . . .  and tuning fork shaped stays.  John Redrup's LRM kit has both options - etched for Dubs, cast brass for B-P.  So if you are inclined to work-up the stays from the etched brass strip, well, good luck with that!   You could turn a suitable bottle-shape and then file the fat part into a stay shape - turn in a drill with a file if you don't have a lathe.

 

If and only if you are going to that much trouble, you might want to thin down the numbers of leaves in the springs themselves - the leading axle bears the biggest lateral stress on bends so is the chunkiest, as you have.  The big-end axle has to flex in multiple ways, so is lightest-sprung - if you are up for it, you could file out the exposed portions of each leaf working from the bottom, to be about 30% thinner than the leading axle springs.  (This applies to all of our steamy-beasties, not just this model.  a six-coupled engine's trailing axle will have spring thicknesses midway between the leading and driven axles.)

[Brassey]

In the absence of anything else, Brassmasters sell an etch of spring hangers under the Martin Finney accessories 

[Crimson Rambler]

I suggest the main reason for the dissimilar number of leaves in the outside springs of Mr Kirtley's double-framed designs such as the 0-4-4T and the 0-6-0 is because he provided the crank-axle with an additional pair of bearings. Two axleboxes were fitted to the inside frames, so the corresponding outside springs only had to carry approximately half the load hence needed fewer leaves. In contrast the leading axle and the trailing coupled axle on the 0-6-0 (and 2-4-0s for that matter) had only axleboxes/springs mounted in the outside frames.

 

 

Crimson Rambler

 

 

[Compound2632]

55 minutes ago, Crimson Rambler said:

I suggest the main reason for the dissimilar number of leaves in the outside springs of Mr Kirtley's double-framed designs such as the 0-4-4T and the 0-6-0 is because he provided the crank-axle with an additional pair of bearings. Two axleboxes were fitted to the inside frames, so the corresponding outside springs only had to carry approximately half the load hence needed fewer leaves. In contrast the leading axle and the trailing coupled axle on the 0-6-0 (and 2-4-0s for that matter) had only axleboxes/springs mounted in the outside frames.

 

Ah, now how did the inner frames and the cylinder block inter-relate? Ahrons suggests that the reason the 800 Class were better engines* than the later inside-framed 2-4-0s, after rebuilding with Johnson boilers etc. (so that they were identical in key dimensions) was that whereas on the inside-framed engines the cylinders were at 2'4" centres, those of the 800 Class were at 2'6" centres, allowing for greater volume of the steam chests. 

 

*In the sense that they could be driven hard with heavy trains, with the regulator well over and late cut-off, without running short of steam. Johnson preferred them on the Scotch Expresses over his own 2-4-0s.

[Crimson Rambler]

I believe Ahrons is correct - the larger steam chest volume would have been of benefit.

 

The inside frames on Mr K's last designs were continuous and extended from the front buffer beam to the drag beam but they rose up and/or were 'notched' as necessary to clear the leading and trailing axles. Some 0-6-0s which were built without continuous inside frames were later given them by adding a bit of new frame after the crank axle.

Mr K's inside frames were usually spaced at 4ft 2ins apart whereas Mr J's standard dimension (but far from exclusive!) was 4ft 1.5ins. The cylinder bores could be spaced wider on the 800 class because the crank axle axlebox loading (the highest loaded) was shared over four 'boxes. Thus the inside 'boxes could be made a bit narrower to permit wider spaced cylinder bores. The designer does not have that opportunity on an inside framed engine because he has to create sufficient space between the outside face of the outermost crank web and the back of the wheel, for an adequate 'box length. Thus the 890 class, which were inside framed, had cylinder bores at 2ft 4ins centres, and in effect all of Mr J's 2-4-0s were simply tarted up versions of the 890/1070 classes, even retaining for example Mr K's long eccentric rods.

 

 

Crimson Rambler 

 

 

 

 

[DayReturn]

4 hours ago, Crimson Rambler said:

I suggest the main reason for the dissimilar number of leaves in the outside springs of Mr Kirtley's double-framed designs such as the 0-4-4T and the 0-6-0 is because he provided the crank-axle with an additional pair of bearings. Two axleboxes were fitted to the inside frames, so the corresponding outside springs only had to carry approximately half the load hence needed fewer leaves. In contrast the leading axle and the trailing coupled axle on the 0-6-0 (and 2-4-0s for that matter) had only axleboxes/springs mounted in the outside frames.

 

 

Crimson Rambler

 

 

I'm not an engineer by profession, at least not in the traditional disciplines, and I'm only relaying what I learnt from someone who is, my friend Alistair Wright.  When I asked him about different spring configurations, this is what he wrote to me:

 

"The leading springs were often made a bit stiffer by adding extra leaves. The axle loading would not be affected as this is set by adjusting the spring hangers, but the spring deflection for any given increase in load would be less. This gives greater stability to a leading set of wheels. The parallel boiler Royal Scots are one loco I know for sure was like this, since I got to adjust the leading springs on one at St Rollox in 1951. The Scots were noted for losing the weight on their leading axle due to the springs relaxing (sometimes due to fatigue cracks in the leaves) and were forever needing adjustment which was normally only done at a main works on a special weighhridge. The PB Scots had an alarming tendency to roll when entering curves at speed. It was quite a simple but tedious, iterative, job, so obviously a CME's pupil who happened to be in the erecting shop that week, got to do it! I have also looked out a drawing I had published in the Modeller of a Kirtley 0-6-0 probably in 1952 or 53, and sure enough it shows the heavier springs!"

 

For myself, I'm not sure that it's correct to say that the number or dimensions of the bearings has a straightforward relationship with the strength of spring required (at least as long as the bearing was doing its job), since there are still the same number of springs and there is only one spring at each end of the axle.  The load (at rest) on the spring would not be changed unless either the inside or outside bearing was in direct contact with the frames, which I don't believe is a desirable circumstance.  In motion, the load would change due to a long list of factors - connecting rod's cycle, acceleration and braking, rail cant, rail joints, designed-in frame flexing and rail flexing, etc.  With a leading rigid axle as in a Victorian 2-4-0, an 0-6-0, or here, in the 0-4-4T, the leading axle will be the first to receive forces *from the track* due to forward motion and then transmit them to the main frame.  That's why reliable bogies became a requirement for faster engines - there's not a lot of technical difference between Johnson's 1400-class 2-4-0 and his 1312-class 4-4-0 except for the bogie in place of the leading axle.  I would have supposed that the inside bearings on the big-end axle on the inside frames are all about preserving the integrity of the axle section between the inner and outer frames and resisting the moment/turning force of the connecting rod against the crank portion of the axle when the frames flex.  If I'm right, then that would be an explanation of why the remaining axles had external bearings only.

 

Anyway, it's a lovely discussion to have, and I'm forever fascinated by the history of the way the associated technologies developed (metallurgy, lubrication, steel making, fluid dynamics, etc.) to allow railway technology to progress.  In our endless enthusiastic "if only, what if, ..." musings we often forget how much of the design of our favourite engines and the ones that annoy us by superseding them, were done at the limits of what was known at the time.  For example here, above, yes the Deeley smokebox looked far less elegant and homogeneous than the Johnson design, but Deeley had a more robust design for maintaining the smokebox vacuum - if the door leaked, the engine was crippled.

Edited September 29, 2021 by DayReturn
class details correction

[Regularity]

This might be of interest/illumination:

 

From this post:

 

[lezz01]

Now that looks like a proper DF loco. 

Regards Lez.

[Crimson Rambler]

I make no comment on later locomotive design practice, my observations are restricted solely to Midland Railway practice and I hope @Mrkirtley800 will agree to me replying to @DayReturn in this topic but as I am not sure how appropriate this is to the Midland Railway in EM Gauge I will keep it short.

 

@DayReturn if, the Alistair Wright you refer to was formerly a LMSS member, then please pass on to him the compliments of a fellow member, although he probably will not know my nom de plume!

 

The Midland 4-4-0s and 0-4-4Ts together with the 2-6-0s were provided with side control whereas the six wheeled engines such as 0-6-0s and 2-4-0s were not. Instead of pony trucks or radial axles they were simply provided with a degree of sideplay - restricted normally to the leading and trailing axles. This was obtained by permitting sideways movement of the axle in its 'boxes and in turn the 'boxes were given a degree of freedom to move sideways in their horn guides.

 

Lower speeds, small/light engines allied with longish wheelbases, coupled also with the coning of the tyres and the inclination of the rails enabled this simple arrangement to function perfectly adequately. In my previous post I was referring specifically to 2-4-0s and 0-6-0s – engines incidentally that together formed the vast majority of the Midland's engines.

 

When in service there is wear so there will have been limits on the permitted increase in sideways movement arising from that before repairs were needed to restore the design values. The wear primarily occurred on the faces of the axleboxes where the axle collars made contact and to a lesser extent on the horn guides. The bearing springs provided no sideways control of the axleboxes. Their purpose was to deal with the up and down movement of the boxes.

 

The following photo (Summerson Vol 4) was taken of Johnson 2-4-0 No.1477 /227 being scrapped in May 1934 having been withdrawn the previous February. The first thing to notice is the impression worn in the face of the frame where the back of the leading wheel has made frequent contact with it. The one-inch thick frames were spaced 4ft – 1.5ins apart, so giving a nominal clearance from the face of the frame to the back of the wheel of 1.0625inch each side (Midland back to back was 4ft – 5.625ins.) The scarring on the frame records the axles have moved sideways in service more that 1.0625ins. By then these engines were very much second or even third tier units so they will not have been given as much attention as they would have received in their prime.

 

 

Seen lying in the right foreground are the remains of the leading portion of the outside frame with its pair of horn guides still bolted to it together with the guide for the push bar that was interposed between the buckle and the top of the outside axlebox.

 

There is also a hint of a second guide but unfortunately the drawings I have seen are unclear on this point, so while I strongly believe it was present this is not confirmed. Either way the push bar was made a reasonably snug fit within the hole provided in the guide. As it was acting in compression the slot in the guide would not accommodate over an inch of sideways movement and still permit the push bar be stiff enough not to buckle.

 

A similar arrangement was fitted to Mr K's outside framed engines differing primarily in that two push bars were fitted – one on the inside of the outside frame and the other its outside. Two guides were fitted per push bar. These were simple 'top hat' brackets on the inside face. The upper one on the outside frame is usually partially hidden by the platform valance while the lower one was incorporated into the top of the hornblock. No sideways movement of the pushbars was provided for in these guides or the holes in the platform, so the springs had no influence on the sideways movement of the axles.

 

A final item of interest are the additional two bearings Mr J provided on the leading axles of his 2-4-0s. The bottom legs of one of the guides associated with these bearings can be seen protruding below the 'ears' of the axle cut-out in the inside frame. The guides contained a small axlebox provided with vertical movement controlled by a pair of helical springs. The latter were restrained at their upper ends by an angle iron fitted to the inside face of the frame behind the slasher - so are not normally seen. However when Mr J rebuilt Mr K's 2-4-0's he introduced a modified version of this arrangement for his predecessor's engines. I can vouch that if you stand on the step of No 158A and peep down between the frames you can see the two additional bearings Mr J fitted.

 

As the spring restraint in Mr K's engines was bolted to the back of the smokebox and the upper portion just peeped above the platform, ensures that it can be often seen in photos.

 

 

Above is a view (Summerson Vol 2) of a 800 Class 2-4-0 No 825 /58 and the upper portion of the two push rods of the additional bearing can be glimsed between the Furness lubricator and the leading spring hanger and the horizontal limb of the L-shaped bracket that received the springs. The vertical limb of the bracket was bolted to the tubeplate - it is just visible. Also to be seen are the two outside push bar guides – those for the leading axle being very clear - together with the rectangular cross-section push bar.

 

 

Crimson Rambler

 

 

[Compound2632]

@Crimson Rambler, so on the inside-framed 2-4-0s, Kirtley and Johnson, the leading axle (which carries the weight of the cylinder block) had both inside and outside bearings?

[Crimson Rambler]

@Compound2632 - indeed.

 

First view is of the 890 class as built:-

 

It only has outside bearings to the leading axle, whereas the following extract of a rebuilt 890 class - Johnson boiler, new cylinders etc, has the additional bearings. The bracket that acts as a stop for the inner bearing springs is bolted to the inside frame in a similar manner to Mr J's 2-4-0s.

 

 

The inside guides protrude down considerably below the bottom profile of the inside frame.

 

 

Crimson Rambler

 

 

 

[PenrithBeacon]

Does that imply that the rebuilds had new inside frames or new cylinder blocks? I'm a little confused! 

[Crimson Rambler]

@PenrithBeaconWhen rebuilt the 890 class were given new cylinders of an SWJ design. These can be distinguished by the valves becoming inclined even though the cylinders remained horizontal.

 

The normal story (Summerson) is that some engines (Nos 890-909) were 'said' to have been given new frames during the 1885-88 rebuilding period while others received them later. Interestingly there are different radii appearing at the bottom of the outside frame in way of the step plate - in the as built engine it is 4.5ins but in the rebuilt engine it has become 5ins. At face value this suggests the outside frames were also changed which I'm not sure about.

 

 

Crimson Rambler.

 

 

[PenrithBeacon]

10 minutes ago, Crimson Rambler said:

@PenrithBeaconWhen rebuilt the 890 class were given new cylinders of an SWJ design. These can be distinguished by the valves becoming inclined even though the cylinders remained horizontal.

 

The normal story (Summerson) is that some engines (Nos 890-909) were 'said' to have been given new frames during the 1885-88 rebuilding period while others received them later. Interestingly there are different radii appearing at the bottom of the outside frame in way of the step plate - in the as built engine it is 4.5ins but in the rebuilt engine it has become 5ins. At face value this suggests the outside frames were also changed which I'm not sure about.

 

 

Crimson Rambler.

 

 

OK, but was the new cylinder block designed with axle bearings included? I gather it was.

The convention for d/f locomotives (or at least it was after Buddicom rebuilt the locomotives the Stephenson's designed for the L&MR) was that the inside frames only carried the driving axle bearings. The outside frame carried bearings for all axles, driving, coupled and carrying. SWJ seems to have changed this convention.  With good reason I'm sure.

[Mrkirtley800]

Hello Crimson Rambler, yes it is OK by me for you to go into detail of what is one of my favourite engines.  I have to admit, I have no idea what you are talking about, but the bits I have picked up are fascinating.

Derek

[lezz01]

Bit of a master class in DF locos, what's not to love?

Regards Lez.

[Crimson Rambler]

With the kind agreement of @Mrkirtley800 I will add a little more in reply to @PenrithBeacon

 

At present I cannot recall an example of a Midland engine where a cylinder was combined with an axlebox guide (but that might mean I'm just not thinking hard enough!). Certainly in several designs the top corners of the guides were cut away to enable the gap between the two to be made as small as practical. During the Kirtly era and for much of SWJ's, the cylinders were cast as 'lefts' and 'rights' and were provided with on their 'sides' with two flanges. One was for where they bolted onto the frame and the other was where the lefthand and righthand castings met on the longitudinal centreline of the engine. This latter flange is visible for example in the two previous photos - (890 Class).

 

Appearing below is a section from the plan of an as built 800 class 2-4-0.

 

There is no bearing fitted to the inside frame and the rear of the cylinder, which coincides more or less with the back of the tubeplate/smokebox, is clear of the leading axle.

 

The following plan extract is of an 890 class 2-4-0 again as built.

 

Once again there is no bearing and the rear end of the cylinder is well clear of the leading axle. As an aside it is interesting to see how close the two designs are. It is clear that the 890's were essentially an inside-frame-only version of the 800s with the cylinder bores put closer together as mentioned earlier by @Compound2632.

 

The final extract shews the equivalent area of a rebuilt 890 class.

The additional bearings have now appeared along with new cylinders but this also ends clear of the guides for these auxiliary bearings. The latter clearly had a small lateral clearance in it guides while its outbord face was recessed to accommodate the collar on the axle as the latter slid across as the engine ran around curves. The outside bearing was given 0.5in sideplay in its guides while the axle would have been given only a nominal clearance in its bearing. On 0-6-0s the equivalent side play was half that but was normally shared between the axle and the box and the box and the guide.

 

I believe the practice of providing four bearings on the crankaxle was to minimize the risk of the engine derailing in the event of its failure - a quite real prospect in the early days and one which I believe Mr Buddicom experienced.

 

I suppose although we oftimes refer to Mr K's designs as being double-framed, to be strictly correct they should really be called outside framed with an inside subsidiary frame that supported the crankaxle. Later of course this subsidiary frame was extended rearwards so that it became continuous from buffer beam to dragbeam thereby stiffening up the complete frame structure while at the same time releasing the boiler so enabling it to expand freely.

 

 

Crimson Rambler