Coach and DMU springing units for Mostyn

Richard Oldfield
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Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Mon Jan 23, 2023 12:46 pm

Hi folks,

The great majority of Mostyn's coaching and npccs bogie stock runs on MJT coach compensation units - partly because that was all there was available when we first started and also because we have had large stocks that are only just being exhausted. We have learnt to deal with the variation in press studs, can knock up running bogies very quickly and the units themselves rarely fail.

The problems that do occur with the MJT CCUs include failures of the soldered joints which secure the torsion bars to the bogie pivots and sides - this can be quite impressive when running long rakes at high speed! A growing problem for Mostyn is axle wear - we have come across axles that, due to high use, have worn down from a standard 25.95 - 26.00mm length to 25.75mm or under. The resultant 'slop' reduces running reliability. Occasionally a wheel may slip on a axle and cause back-to-back issues.

It would be a fair comment to say that Mostyn is a special case with its heavy use and high speeds - and it is not the fault of the CCU that the axles get worn or wheelsets may drift out of specification.

The general problem is that the MJT CCUs are not straightforward to repair and/or maintain, especially after bogie sideframes and other details have been added. Removal of wheelsets is a pain as it nearly always distorts the CCU unless you unsolder one side. This can be a niggly issue when at the testing, painting and weathering stages of a project.

With the impetus of a number of future coaching stock and DMU builds in the pipeline, Barrowmore MRG members Colin Craig and David Faulkner have developed a new springing unit design which aims to :-

1. Offer a simple springing arrangement (allowing simple changes of springs if required).
2. Enable wheelsets to be removed without dismantling or distorting the springing unit.
3. Allow the model builder to choose their own preferred cosmetic sideframes.

The units work on the same principle as Colin's work on freight bogies but have more widely spaced spring pivot supports.

Having gone through several design iterations we think the 'Mostyn' coach springing unit is now ready for some external comments and suggestions.

Here is the 'kit' - instructions will follow in this thread if there is interest.

Coach Springing Unit Contents.jpg


Cheers,

Richard
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grovenor-2685
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Re: Coach and DMU springing units for Mostyn

Postby grovenor-2685 » Mon Jan 23, 2023 2:29 pm

Richard Oldfield wrote:A growing problem for Mostyn is axle wear - we have come across axles that, due to high use, have worn down from a standard 25.95 - 26.00mm length to 25.75mm or under. The resultant 'slop' reduces running reliability.

Interesting, I would expect, with steel axles in brass bearings, that it would be the bearings that wear. If your axles are worn down to that extent what condition are the bearings in?

I would have offered a beta test but my layout is not currently in a condition where I could give them a suitable test. So I could only comment on buildability.
Second thoughts I could give them a run on the MRC test track.
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Keith
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Neil Smith
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Re: Coach and DMU springing units for Mostyn

Postby Neil Smith » Mon Jan 23, 2023 3:33 pm

This could be timely given the possible loss of the Bill Bedford sprung bogie subframes, with the demise of Eileen's, if you were prepared to release them for sale somehow?

Do they have the option of secondary springing which would then completely replicate what was on offer with the BB ones?

And could they be in differing wheelbases, and perhaps with a simpler side profile to suit older bogies as well?

All the best

Neil

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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Mon Jan 23, 2023 3:58 pm

Hi Keith,

Richard Oldfield wrote:A growing problem for Mostyn is axle wear - we have come across axles that, due to high use, have worn down from a standard 25.95 - 26.00mm length to 25.75mm or under. The resultant 'slop' reduces running reliability.

grovenor-2685 wrote:Interesting, I would expect, with steel axles in brass bearings, that it would be the bearings that wear. If your axles are worn down to that extent what condition are the bearings in?


I have not had a good look at the bearings - the problem normally arises at an exhibition and my sole focus at that point is getting the vehicle back in reliable running condition. You can usually see the 'bluntness' on the outer points of the axle and, with certainty, replacing the offending wheelset with a new wheelset sorts out the issue.

grovenor-2685 wrote:I would have offered a beta test but my layout is not currently in a condition where I could give them a suitable test. So I could only comment on buildability.
Second thoughts I could give them a run on the MRC test track.


Thank you for your kind offer - which we may take up in due course when we have satisfied ourselves that this design works as intended.

Cheers,

Richard

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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Mon Jan 23, 2023 4:19 pm

Hi Neil,

Neil Smith wrote:This could be timely given the possible loss of the Bill Bedford sprung bogie subframes, with the demise of Eileen's, if you were prepared to release them for sale somehow?


Provided it can be done in such a way that it does not detract from our normal modelling activities then we will make these springing units available after we are fully satisfied that they work as intended.

Neil Smith wrote:Do they have the option of secondary springing which would then completely replicate what was on offer with the BB ones?

No, they do not have the option of secondary springing. I am sure the Bill Bedford products will return through another route at some point to satisfy those who want this feature. We have been working on this project for some time and the current unavailability of Bill Bedford's products is simply a coincidence.

Neil Smith wrote:And could they be in differing wheelbases, and perhaps with a simpler side profile to suit older bogies as well?

We are focussed on requirements for Mostyn (Mk1, Mk2, Mk3, HST, DMUs and some parcels stock) and have started with 8' 6" wheelbase bogies in two variants - for 3' and 3' 6" wheelsets. We have no intention of producing a wide range but would try and help if possible.

Cheers,

Richard

(edited to correct spelling of secondary)

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Neil Smith
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Re: Coach and DMU springing units for Mostyn

Postby Neil Smith » Mon Jan 23, 2023 4:35 pm

Thanks Richard, fingers crossed your testing and commissioning all goes well. And I fully get that the priority is for sizes and styles that will be needd on Mostyn.

But if they do become avaiable beyond Mostyn at some point, I can seem them being helpful!

All the best

Neil

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ChrisMitchell
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Re: Coach and DMU springing units for Mostyn

Postby ChrisMitchell » Mon Jan 23, 2023 5:14 pm

Richard.

They look excellent, and at first glance would appear straightforward to use.

I would be keen to acquire a number of sets if you decide to make them available to a wider audience

Regards, Chris

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Re: Coach and DMU springing units for Mostyn

Postby grovenor-2685 » Tue Jan 24, 2023 10:45 am

Richard Oldfield wrote:Thank you for your kind offer - which we may take up in due course when we have satisfied ourselves that this design works as intended.

OK, whenever. I took it that you were asking for help in satisfying yourselves. :)
Richard Oldfield wrote:Having gone through several design iterations we think the 'Mostyn' coach springing unit is now ready for some external comments and suggestions.
Regards
Keith
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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Tue Jan 24, 2023 4:45 pm

Hi,

The 'kit' comes with the following contents :-
Coach Springing Unit Contents.jpg


- main springing unit fret
- small fret for spring location tool
- 2 x brass rotation collars
- 2 x 2mm brass nuts
- 2 x 2mm x 8mm long stainless steel set screws
- 4 x 0.0115" x 36mm guitar wire

Suggested construction method:-

1. Spring location tool. Separate from fret and fold over 180 degrees (half etch on outside). Solder sparingly to laminate halves ensuring no solder penetrates the half-etched tabs - which form an important slot. The other end of this tool is a slot clearance tab which is useful if there is any under-etching. Put this to one side for now.

spring location tool.jpg


2. Remove main bogie etches and bogie pivots from fret. Fold bogie pivot legs 90 degrees and insert the bogie pivot through the top face of main bogie etch. Splay legs slightly and then solder in place. Snip off protruding tabs and clean lower surface smooth.

bogie pivot fitting top face.jpg

bogie pivot fitting lower face.jpg

bogie pivot fitting lower face cleared.jpg


3. Fold all brake shoes 180 degrees (half-etch always on outside). Ease outer pairs of shoes slightly upwards to facilitate soldering along the inner faces. Ease inner pairs of shoes slightly downwards to solder them together along their inner faces.

brake shoe soldering.jpg


4. Fold sideframes 90 degrees. It is critical to ensure the sideframes are not splayed as this will introduce 'slop' to the wheelsets. Check carefully.

fold sideframes.jpg


More to follow .....

Cheers,

Richard

Edited 25/1/23 to correct the diameter of the spring wire following an observation in a subsequent posting.
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Last edited by Richard Oldfield on Wed Jan 25, 2023 12:25 pm, edited 1 time in total.

Jeremy Suter
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Re: Coach and DMU springing units for Mostyn

Postby Jeremy Suter » Tue Jan 24, 2023 6:16 pm

Hi Richard
Very nice new item.
I assume its a test etch and you will be correcting the brakes.
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Richard Oldfield
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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Tue Jan 24, 2023 7:58 pm

Hi Jeremy,

Jeremy Suter wrote:Very nice new item.
I assume its a test etch and you will be correcting the brakes.


Thank you for your kind comment.

If you look carefully at the location and orientation of the half-etched fold lines then it can be seen that the brake shoes fold into the correct position.
(or is it something else about them that is causing concern?)

Cheers,

Richard

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Winander
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Re: Coach and DMU springing units for Mostyn

Postby Winander » Tue Jan 24, 2023 8:54 pm

For stage 3, it does, of course, depend which way up the fret is when the shoes are bent upwards and downwards. The photograph shows it is in the orientation it will be in when installed, but it may be worth emphasising the fact in words. Otherwise the brakes shoes will be bent part-way in the wrong direction.
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essdee
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Re: Coach and DMU springing units for Mostyn

Postby essdee » Tue Jan 24, 2023 10:12 pm

......??
I am with Jeremy; I can only see the outer brake shoes, even when correctly folded up, facing away from the wheels?

But a lovely piece of etching otherwise, so far.

Steve

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Re: Coach and DMU springing units for Mostyn

Postby grovenor-2685 » Tue Jan 24, 2023 10:27 pm

See the fold lines on the next to last pic.
First fold is 180 on the fold crosswise to the bogie, then
second fold brings the shoe down in the correct place.
Clever stuff.
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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Tue Jan 24, 2023 10:33 pm

Hi Steve,

essdee wrote:......??
I can only see the outer brake shoes, even when correctly folded up, facing away from the wheels?


I am trying not to jump the gun in terms of the sequence of the build but try to visualise this in the image below step 3.

- first of all make a 90 degree fold at an outer brake shoe along the short half-etched line which is horizontal in the image so that the brake shoe comes up vertically.
- next make a 180 fold along the short half-etched line which is vertical in the image. This has the effect of rotating the brake shoe through 180 degrees so it is facing downwards and in the correct orientation.

Hope this helps and, if it doesn't, all will be clear when I post the next steps.

Cheers,

Richard

essdee
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Re: Coach and DMU springing units for Mostyn

Postby essdee » Tue Jan 24, 2023 11:06 pm

Keith, Richard,

Thanks! Yes - I have it now - very neat as Keith says.

Cheers,

Steve

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Re: Coach and DMU springing units for Mostyn

Postby zebedeesknees » Wed Jan 25, 2023 12:11 pm

Richard, I am looking forward to understanding how the springing system works, not being familiar with Colin's bogie design. The bearing carrier idea looks interesting.

In the parts list, I presume that the wire diameter given is a typo, should it read 0.0115" or perhaps 0.015"? The latter would indicate rather heavy carriages.

And will there be alternative bogies for 3'0" dmu and 3'7" wheelsets?

Ted.
(A purists' purist)

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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Wed Jan 25, 2023 12:36 pm

Hi Ted,

Thanks for your comments and interest.

zebedeesknees wrote:Richard, I am looking forward to understanding how the springing system works, not being familiar with Colin's bogie design. The bearing carrier idea looks interesting.


I will post more on Friday as I'm meeting up with Colin tomorrow to work on some other projects.

zebedeesknees wrote:In the parts list, I presume that the wire diameter given is a typo, should it read 0.0115" or perhaps 0.015"? The latter would indicate rather heavy carriages.


Oh dear, senior moment on my part! - it should read 0.0115" and I have now edited the original posting to correct it.

zebedeesknees wrote:And will there be alternative bogies for 3'0" dmu and 3'7" wheelsets?

Yes.

Cheers,

Richard

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Will L
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Re: Coach and DMU springing units for Mostyn

Postby Will L » Wed Jan 25, 2023 3:07 pm

Richard Oldfield wrote:
zebedeesknees wrote:Richard, I am looking forward to understanding how the springing system works, not being familiar with Colin's bogie design. The bearing carrier idea looks interesting.


I will post more on Friday as I'm meeting up with Colin tomorrow to work on some other projects.

I'm with Ted. I worked out for myself how the brake block/hangers worked but I'm still unsure about the springing. I wasn't sure I dare ask in case it was obvious and I'd just missed the plot. Bring on Friday.

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Re: Coach and DMU springing units for Mostyn

Postby grovenor-2685 » Wed Jan 25, 2023 3:20 pm

Plenty of clues there Will, I can only see one possibility.
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Re: Coach and DMU springing units for Mostyn

Postby Proton » Wed Jan 25, 2023 8:14 pm

Can I be entirely selfish for a moment, and wonder if you will be offering a six-wheel kit for the LMS 12-wheel vehicles? I have about 100 8-wheel passenger cars running quite well, Brassmasters being number one for reliability, and the MJT versions being a close number two as long as I fettle the stud fastener. I have attempted to build the BB 6-wheel sprung bogie, but its too fiddly for my liking.

John

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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Fri Jan 27, 2023 11:17 am

Hi John,

Proton wrote:Can I be entirely selfish for a moment, and wonder if you will be offering a six-wheel kit for the LMS 12-wheel vehicles? I have about 100 8-wheel passenger cars running quite well, Brassmasters being number one for reliability, and the MJT versions being a close number two as long as I fettle the stud fastener. I have attempted to build the BB 6-wheel sprung bogie, but its too fiddly for my liking.


I'm afraid that, unless you can turn up evidence that LMS 12-wheel vehicles lasted into Mostyn's time period of 1977, we are unlikely to see their bogies as a priority for us ...... but let us get our current ideas up and running first and we'll see where it goes.

Cheers,

Richard

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Re: Coach and DMU springing units for Mostyn

Postby Proton » Fri Jan 27, 2023 11:24 am

Point taken, Richard, and I am quite sure there weren't any twelve-wheelers around in '77!

John

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Re: Coach and DMU springing units for Mostyn

Postby Richard Oldfield » Fri Jan 27, 2023 11:43 am

Hi,

Moving on with the construction of the coach springing unit:-

5. Fold the ends up 90 degrees.
Coach Springing Unit end folds.jpg


6. Central spring support. Fold the two wings 90 degrees with the half-etch on the inside and then fold the entire spring support assembly 180 degrees with the half-etch on the outside such that it is hard up against the inside face of the springing unit solebar. Fold the central tabs (which are either side of the central springing support) at 90 degrees with the half-etch on the inside.
Coach Springing Unit central tab folding.jpg


7. Brake shoe folding. Fold the inner pairs of brake shoes 90 degrees with the half-etch on the inside. The outer pairs of brake shoes are a two-stage fold - first make a 90 degree fold with the half-etch on the inside along the half-etched line nearest the brake shoe itself and then make a 180 degree fold with the half-etch on the outside along the half-etched line nearest the end of the springing unit.
Coach Springing Unit brake shoe position.jpg


8. Key soldering stage. Solder to ensure all brake shoe, tab, wing and solebar joints are reinforced. In particular ensure the 180 degree fold to keep the outer pairs of brake shoes in position plus the solebar/end joint is strengthened. The solebars are quite thin (so they do not protrude beyond modern bogie sideframes) and need all the support they can get.
Coach Springing Unit main soldering stage.jpg


Cheers,

Richard
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Paul Townsend
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Re: Coach and DMU springing units for Mostyn

Postby Paul Townsend » Fri Jan 27, 2023 4:30 pm

What is the etch thickness, it looks like 18 thou


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