MRJ 234

[billbedford]

Do you know how many flange profiles (and depths of course) are actually running over the national network every day?

Last time I look at wheel profile there are about a dozen profile defined, but only about half of them are in regular use.

 

Good article in MRJ 234 about Pendon buildings btw but it's a shame about some of the inaccuracies inadequacies in the article about Dewsbury goods  Maybe it helps to have a  wider knowledge and experience of the real thing?  (although having been involved with it for over 40 years I was never surprised at being told how little we allegedly knew about our own jobs )

I thought Dewsbury looked far to clean for Edwardian West Yorkshire, na'much brass there.....

[Siberian Snooper]

On one of my visits to a Laira open day I had a look at the wheel profiling machine in action and there were a number of different cutters for different locos, dmu's and rolling stock. Do the P4ers and S4ers use different wheel profiles? As per prototype or are they mostly incorrect.

[Bernard Lamb]

 

 

Like all standards, P4 has a "tolerance", but if you have something outside that standard then the results will not be "optimum". 

 

 

If you have something that is well within the tolerance it might well not be "optimum".

The whole point of a tolerance is to give you the max and min acceptable dimensions. The optimum dimension will in many cases be of a much smaller range.

Neither extreme should be approached let alone reached.

Even the go no go gauges mentioned recently should, if designed and made correctly, not allow the maximum tolerance as shown on the drawing that sets out the standards.

For non engineers I better explain. There must be a working tolerance on the dimensions used to make the gauge and this tolerance has to be included in the total tolerance allowed on the part.

Bernard

[Horsetan]

....Do the P4ers and S4ers use different wheel profiles? As per prototype or are they mostly incorrect.

No, we use differing flangeway gaps.

[billbedford]

Do the P4ers and S4ers use different wheel profiles? As per prototype or are they mostly incorrect.

 

P4 & S4 wheels are based on the ARLE "A" profile, i.e. The 'standard' profile used by British Railways. This is mainly for historical reasons, in that the ARLE profile were current on the big railway when the Scalefour wheel standard were being drawn up. 

[Re6/6]

I thought Dewsbury looked far to clean for Edwardian West Yorkshire, na'much brass there.....

 

Agreed, although a superb model, there isn't a weed inside the railway fence!

[Horsetan]

I've still got Alan Bennett narrating in my head.

[The Stationmaster]

Agreed, although a superb model, there isn't a weed inside the railway fence!

It is definitely far too clean but the odd thing I noticed is that it seem to have virtually no space at all to handle goods mileage traffic (and no mention of it either) which surely would have been quite an important feature of a depot like that in a town in the woolen industry?

[t-b-g]

Usually wheels accumulates crud when they are not making equal pressure on the rail which is why some form of suspension is recommended in P4 as there is less flange to play with at the start.

 

Cheers,

 

David

 

The problem with some types of suspension arrangements are that you don't get equal downwards pressure on all wheels. The worst offender amongst my layouts has every wagon sprung with individual springs on each wheel. In many cases, one wheel ends up caked in muck and the others remain clean. It is very difficult indeed to measure the downward pressure and make adjustments so all you can do is tweak the spring on the errant wheel and hope you don't make things worse on another wheel!

 

What amazes me is when I see folk advocating P4 with things built rigid (apart from the small natural "play in bearings etc.). I know people who have made P4 work and work very well indeed but they wouldn't dream of having a converted RTR wagon or loco on their layouts with a straight wheel replacement. Yet people say that it works and who am I to doubt them! It is another case of what should work and what does work being different. Their trackwork and baseboards must be magnificently flat, far better than I can manage.

 

Tony

[clecklewyke]

 

It is only necessary to keep restating these facts because of the carping comments of the nay-sayers.  Those of us using these variant standards have been doing so for years, and what we have been saying about it is derived from extensive practical experience; it does not just rely on theory or calculations.  All we ask is that the theorists and the 'purists' (see my definition of this term above) simply accept that some of us have found such deviations from the published P4 standards to be entirely practical and even advantageous.

 

Whilst it is clear that Crichel Down and a few others have successfully used these deviations from the P4 standards it is equally true that very many more people have used the published standards with equal success. They can work, as anyone who has operated Mike Norris' Preston - by any standards a large, complex railway -  or Tim Venton's Clutton can vouch. I moved to P4 standards in the 1990s when I was finding the variation in OO standards very frustrating and P4 was consistent, so any problems were down to my poor craftmanship. Possibly more modern OO will work much better - but it's too late now for me.

 

Anyway, back to MRJ.

 

I really enjoyed and was inspired by the Dewsbury article. I leave others to explain Stationmaster's comment about "mileage" traffic. I remember the term from many of CJF's "Plans of the Month" and never understood it but I would have thought that the Bob Essery, the author of so many articles and books on goods traffic working, would have got that right.

 

My only criticism of his Dewsbury is that, although the railway buildings and infrastructure look good (and they probably would have been much cleaner and tidier in his period than in later years - the railway he modelled would have been brand new) the other buildings did not bring to mind the real Dewsbury. They all seemed to be in brick and derived from prototypes from somewhere down south, whereas they should have been mostly stone and displayed the local vernacular. I think Geoff Taylor has captured the look of West Riding stonework much better in the MRC's OO model of "Dewsbury".

 

Nevertheless, a superb issue, full of inspiring articles

.

 

Ian

[davknigh]

The problem with some types of suspension arrangements are that you don't get equal downwards pressure on all wheels. The worst offender amongst my layouts has every wagon sprung with individual springs on each wheel. In many cases, one wheel ends up caked in muck and the others remain clean. It is very difficult indeed to measure the downward pressure and make adjustments so all you can do is tweak the spring on the errant wheel and hope you don't make things worse on another wheel!

 

What amazes me is when I see folk advocating P4 with things built rigid (apart from the small natural "play in bearings etc.). I know people who have made P4 work and work very well indeed but they wouldn't dream of having a converted RTR wagon or loco on their layouts with a straight wheel replacement. Yet people say that it works and who am I to doubt them! It is another case of what should work and what does work being different. Their trackwork and baseboards must be magnificently flat, far better than I can manage.

 

Tony

I have wagons of all faiths on my 2 P4 layouts and find compensated wagons to be the most likely to offend by derailing but only by a narrow margin. One factor not mentioned is weight, all of mine are at least 45g which makes a big difference in track holding ability. None of this eliminates the need for making sure that track and wheels are up to standards but if they are much can be done, even with straight drop in replacements. Even dead flat track isn't needed, just sudden changes in elevation need to be avoided at all costs, and oh yes, reasonable operating speeds.

 

Cheers,

 

 

David

[sp1]

I have wagons of all faiths on my 2 P4 layouts and find compensated wagons to be the most likely to offend by derailing but only by a narrow margin. One factor not mentioned is weight, all of mine are at least 45g which makes a big difference in track holding ability. None of this eliminates the need for making sure that track and wheels are up to standards but if they are much can be done, even with straight drop in replacements. Even dead flat track isn't needed, just sudden changes in elevation need to be avoided at all costs, and oh yes, reasonable operating speeds.

 

Cheers,

 

 

David

I know you are referring to wagons with your post - but what about bigger layouts with 90mph expresses: what is done to p4 coaches?

[t-b-g]

I have wagons of all faiths on my 2 P4 layouts and find compensated wagons to be the most likely to offend by derailing but only by a narrow margin. One factor not mentioned is weight, all of mine are at least 45g which makes a big difference in track holding ability. None of this eliminates the need for making sure that track and wheels are up to standards but if they are much can be done, even with straight drop in replacements. Even dead flat track isn't needed, just sudden changes in elevation need to be avoided at all costs, and oh yes, reasonable operating speeds.

 

Cheers,

 

 

David

 

Weight can make a huge difference as long as all the wagons are the same and as long as trains are not so long that the weight causes haulage problems.

 

I am interested to know if you have investigated the reasons why compensated wagons derail, more than others. I have found the same in EM and now build mine rigid, which seems to give no trouble at all and now any derailments I have seem to be down to operator error or mechanical failure (such as a broken soldered joint on a point tie bar).

 

I never took the trouble to establish why that was the case, I just stopped building compensated ones!

 

I don't know how many derailments you get in total but is there any chance at all that the approach outlined in MRJ might reduce that number?

 

Tony

[t-b-g]

I know you are referring to wagons with your post - but what about bigger layouts with 90mph expresses: what is done to p4 coaches?

 

The only time I have seen such trains running in P4 was with sprung bogies based on the designs of Chris Pendlenton and described in an MRJ some time ago. 12 carriages behind an A3 was quite something. That is the only layout I have seen such running on with steam locos though. Mostyn and Calcutta Sidings are examples where long trains run quite fast with more diesel traction but I don't know what they do with their bogies.

[Captain Kernow]

I started off by compensating or springing all my P4 wagons, whether kits or converted R-T-R. However, I hardly ever do anything to modern R-T-R, other than ensure that the wheelsets run nice and true, spruce up the brake gear a bit and put lots of weight in them. If they don't derail on our area group test track, then they probably won't derail elsewhere (not that they are likely to run elsewhere, other than on my own layout, where all is well).

 

The mention of ensuring consistent weight of all such wagons is important. One concession I do make, if I can, is to fit sprung buffers, as I find this helps when propelling.

 

Anyway, back to the issue concerned - apart from the heinous sacrilege regarding the wheels piece, and the Alan Bennett-narrated article on Dewsbury, what grabbed my attention most was the Lower Soudley article. I've admired the layout at a show (Wells a few years ago), and it's nice to see it in print. Not enough decent Forest of Dean layouts in my view...

[pete_mcfarlane]

P4 & S4 wheels are based on the ARLE "A" profile, i.e. The 'standard' profile used by British Railways. This is mainly for historical reasons, in that the ARLE profile were current on the big railway when the Scalefour wheel standard were being drawn up. 

Wasn't there a load of research done at Derby in the late 1960s in to wheel profiles and wheel/track interaction? So more modern stock (especially high speed stuff) may have different wheel profiles based on this research. 

[Colin parks]

I was pleased to read through my friend Howard Bolton's description of his track-laying methods in the latest MRJ. I just wish there had been more colour photos of Howard's track work as his colour treatment on rail and timbering is about the best I have seen - even down to the oil stains on slide chairs.

 

I am looking forward to the next instalment!

 

Colin

[davknigh]

I know you are referring to wagons with your post - but what about bigger layouts with 90mph expresses: what is done to p4 coaches?

Coaches? Well, that nice Mr Bedford makes some excellent sprung bogies (usual disclaimer) that I'm sure would help but my experience in this field is limited as I don't have the room to get a train up to 90mph . Obviously good track is a must but the short wheel base of the bogies is a help and if they are built square I suspect the need for a suspension is minimal (but I could very well be wrong).

 

Cheers,

 

David

[davknigh]

Weight can make a huge difference as long as all the wagons are the same and as long as trains are not so long that the weight causes haulage problems.

 

I am interested to know if you have investigated the reasons why compensated wagons derail, more than others. I have found the same in EM and now build mine rigid, which seems to give no trouble at all and now any derailments I have seem to be down to operator error or mechanical failure (such as a broken soldered joint on a point tie bar).

 

I never took the trouble to establish why that was the case, I just stopped building compensated ones!

 

I don't know how many derailments you get in total but is there any chance at all that the approach outlined in MRJ might reduce that number?

 

Tony

Tony,

 

Like you I just gave up on the compensated wagons (MJT inside compensation units) after finding that they were no better than ones built square with a bit of end play and a little weight. That said, I do like sprung W-irons for the looks and the smoother ride they give. I've found that my derailments are generally down to a few causes; wagons built out of square, wheels slipping out of gauge (don't ask me how this happens, it just does), wheel crud, and sudden changes in elevation in the track due to solder joints failing. Some wagons (and I'll regret saying this) never derail regardless of suspension type. As to whether the approach outlined will work, dunno,  MRJ 234 has yet to make it to our shores, 233 only having just arrived last week, but I'll give it a look.

 

Cheers,

 

David

[Guest Lyonesse]

Very interesting discussion.

 

Re EM/P4/S4, the essential element of any set of standards is how closely they can be achieved.  Any fool can divide a set of prototype dimensions by 76.2 and call it a standard but that is not the same as devising a set of consistent dimensions with full tolerances, and rigidly sticking to them.

 

The fact is that it is simply not possible to work to scaled down prototype dimensions.  In part this is because few of us have served a 7 year toolmakers' apprenticeship, or have access to serious machine tools and measurement equipment.  (Not a cheap, Chinese, digital caliper set.)  To keep wheelset runout to within 10s of microns requires a very stiff, one-piece, metal construction.  Plastic centred steam loco wheels are too flexible to maintain runout to better than about 0.2mm.

 

My dream is to one day run some serious, non-contact measurement equipment over a so-called scalefour layout, proving to the owner that it is no such thing and that his track gauge varies by 0.5mm.

[The Stationmaster]

 

Anyway, back to MRJ.

 

I really enjoyed and was inspired by the Dewsbury article. I leave others to explain Stationmaster's comment about "mileage" traffic. I remember the term from many of CJF's "Plans of the Month" and never understood it but I would have thought that the Bob Essery, the author of so many articles and books on goods traffic working, would have got that right.

 

Ian

Goods traffic (as opposed to, say, 'coal and mineral traffic') came in two basic kinds 'mileage traffic' and 'small consignments' (usually called 'smalls' in the industry and in later years known as 'sundries'.  Mileage traffic was often referred to in later days as 'wagonload traffic' and that, in some respects, more specifically explains what it was - it was traffic loaded to a wagon and making the full load for that wagon.  Whereas on the other hand smalls were mixed consignments in a wagon.

 

This the very nature of the two immediately starts to set them apart and perhaps begin to indicate that they were handled differently.  Loading a wagon with smalls meant that you needed somewhere to bring the various consignments together at the sending station and somewhere to separate them at the receiving station which in turn meant the wagons had to be in position for as long as the various operations took and it also meant that what came out of them had to be somehow sorted - either for delivery or possibly for collection by the consignee.  Equally when you think about it outward smalls meant that consignments arriving - either from collection or brought in by the consignor - needed sorting if the station concerned was forwarding wagons to more than one destination.  

 

And all of this sorting work required a space in which it could be done with easy access to/from wagons and, in most instances, equally easy access to/from delivery/collection vehicles, and if it could be done undercover all the better, and if there was somewhere to readily do all the associated paperwork better still - and what could be better than a goods shed, and that is just what they were for (and some even incorporated warehouse space where consignments originating from a single consignor could be held for forwarding or delivery on consignor's instructions or equally traffic could be held for a consignee.  At many larger stations completely separate warehouses were provided - but serving the same purpose).

 

In contrast mileage traffic was much more straightforward - it was a simply a stage in the transit between consignor and consignee and quite often might even be handled to or from their delivery/collection vehicles; it didn't need sorting, the paperwork was very simple, and although some of it required craneage a lot of it could simply be moved from wagon to road vehicle or vice.  All that needed was a siding with suitable road vehicle access and, possibly a crane or access for a crane.

 

At larger depots mileage traffic (other than coal and minerals) might be dealt with under cover, separately from small traffic. but at the vast majority of places there was no such luxury and the traffic was handled in a mileage yard or on a 'mileage road' (or roads) in the goods yard and possibly quite near the goods shed.  Occasionally, especially in later years (post WWII I would say) a kind of open side extension might be added to a goods shed to ease the handling of some mileage traffic such as barrels but very often such extensions were there just to enable more wagonloads of smalls to be dealt with at a time with the sorting still going on in the adjacent shed.  And of course in some larger towns etc there were completely separate mileage depots in just the same way as there could be completely separate depots for coal class traffics.

 

Basically just as simple as that but like so many things on the railway if you've never been involved in it or directly with it you might not necessarily fully realise what went on beyond your own part of the job.  All too easy to forget nowadays that the railways were a vast industry involving a huge range of trades and skills where what you saw of someone else's job could give you no more than a small impression of it - should you see any of it at all.  Some of us on the slightly more traditional railway had the good (??) luck to be involved in far more than a single part of it and to see or experience at close hand the detail of many different facets of our industry but the vast majority never had that luxury.  Fortunately I had the benefit of experience of station level work in passenger, goods and parcels as well as both large freight and passenger yards but for many that was never the case.

[Brian Harrap]

Very interesting discussion.

 

.  Any fool can divide a set of prototype dimensions by 'whatever'

I was the fool that did just that and look where its got me. B.

[davknigh]

Lyonesse, on 19 Oct 2014 - 08:40, said:

My dream is to one day run some serious, non-contact measurement equipment over a so-called scalefour layout, proving to the owner that it is no such thing and that his track gauge varies by 0.5mm.

 

Go on then, I'm sure the lads at Calcutta Sidings or Mostyn would be pleased to accommodate you... I would too but you'd have to pay your own air fare

 

Cheers,

 

David

[Guest Lyonesse]

 

Lyonesse, on 19 Oct 2014 - 08:40, said:

My dream is to one day run some serious, non-contact measurement equipment over a so-called scalefour layout, proving to the owner that it is no such thing and that his track gauge varies by 0.5mm.

 

Go on then, I'm sure the lads at Calcutta Sidings or Mostyn would be pleased to accommodate you... I would too but you'd have to pay your own air fare

 

Cheers,

 

David

 

Thanks for the offer of the air fare.

 

I was maybe not clear.  I am not sitting at home, bitter and twisted in my temperature controlled metrology lab, awaiting the summons to prove that xyz layout is a scale 1/8inch under gauge.  I merely doubt the existence of true scalefour railway modelling and wish I had the means and opportunity to prove it.

 

I am the first to cheer when people give up their hard earned time and money to build a working model railway.  I just think that 'scale' models generally stay on the rails because of much larger than scale tolerances and flexibility, not despite it.

[queensquare]

Regrettably nothing unusual about that though, I get similar muppetry regarding aviation.

 

More fool you, I'd never get on a plane flown by a muppet  

 

Jerry