Model Railway Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
2,693 Posts
Some nice modelling there Cameron - well done.

Just some comments on a couple of topics in this thread:

Cambridge Custom Transfers

I have used these in the past and not found them to be particularly good at adhering to models. Like you, I airbrushed varnish over them. In the process, I found that the 'letters' are very susceptible to the formulations of varnishes. In some cases, I found that the 'ink' of the letters was dissolved and in other cases, the letters were dislodged.
In the end, I ended up binning them and buying better transfers such as HMRS.

Parting of W Irons

I note that you mentioned issues with the construction of a brass kit as being unusual to accomodate wheel fitting.
This is actually an issue I come across frequently, having built 100's of wagon kits, both in 4mm and 7mm scales.

In my opinion, many kit manufacturers give poor advice on constructing chassis. Most advise to build the chassis and then prise the W irons apart to force-fit the wheels.
Personally, I think this is really bad advice.
My approach is to build the chassis of all rolling stock by fitting the solebars and W irons to the 'base plate' and at the same time, fitting the wheels as one side solebar is fitted. This means that there is no bending of W irons and the W irons stay as a tight fit, preventing sideplay in wheels sets. Using this approach also ensures that the chassis is square and the the wheels sit on the rails with no wobble. You have to get this bit right otherwise a model will never run well.
Too many kits advise building the body first and attaching the chassis to it. This is too late! Once the body is twisted, a chassis can never be square and a model can never run well unless the kit is particularly well manufactured.

I suspect that a lot of this also originates from the RTR manufacturers who mould their models and then prise W irons apart to fit wheels. As a result, many RTR models have a lot of side-play. Dare I say it, Dapol 7mm wagons are particularly bad in this respect.

Keep up the good work!
 

·
Registered
Joined
·
2,693 Posts
I've described my 7mm experiences of side-play here: Building the Parkside PO Mineral Wagon Kit - Model Railways On-Line
and here: Review of the Lionheart 7mm scale BR(WR) B Set - Model Railways On-Line

I can't say I have had a problem with any Bachmann wagons with W irons splaying out or bearings wearing out.
I have plenty of Airfix/GMR too and haven't had a problem with them either.

But all of them are manufactured to have the wheels post fitted. That's the way they are.

With kits, it is a different situation. Generally, the W irons are much more fragile than RTR which is why I recommend constructing chassis and fitting the wheels at the same time as the solebars are glued to the base plate so that the W irons don't need bending apart to fit the wheels later - your [Cameron's] step 4. I would add that once the glue has partially set, I do check for squareness and sitting flat on rails/glass sheet before I allow it to set fully. I dry run fit to ensure that I don't have W irons tilting inwards or outwards - sadly, this is quite a big problem on Parkside 7mm kits.

I too had issues with CCT transfers having printing faults, including the 'ink' becoming detatched from the backing before the transfers were even applied.
Agreed that they fill the gaps where other suppliers don't, but they don't feature very high on my list of choices.

My experience of Adrian/ABS kits is with this 7mm kit: ABS 12T Goods Van Kit - Model Railways On-Line
This one has an all-brass body and cast white-metal chassis. It is solid and quite heavy.

I am a big advocate of kit building wagons and would encourage everyone to have a go. We are blessed with so much variety from Dapol, Parkside, Cambrian, Ratio/Peco and many others. They are a quick and cheap way to build up a fleet very quickly which is also different to RTR products. Some of mine:

https://modelrailways.online/Pages/Vu/BuildingtheDapolMeatVanKit
https://modelrailways.online/Pages/Vu/BuildingtheParksideBRFruitVanKit
https://modelrailways.online/Pages/Vu/BuildingtheParksideBRStandardVanKit
https://modelrailways.online/Pages/Vu/BuildingtheParksideGWRMinkGKit
https://modelrailways.online/Pages/Vu/Weathering16TMineralWagons
 

·
Registered
Joined
·
2,693 Posts
Just a further comment on chassis squareness: in 4mm scale we generally just make sure that the axles are perpendicular to the rails and the wheels sit firmly on the rail heads with no rocking and provided this is sorted, you're good to go. In 7mm, you begin to understand the issues of the prototype because if you don't build a chassis squarely, the effects of the prototype start to come into play. For example, if you don't get the axles dead-perpendicular to the rails, a vehicle will 'hunt' (move sideways) from one side to the other as it changes direction and will appear 'out of line' with other vehicles in a train. This of course, does depend on what your wheel/rail standards are, but in current 'finescale' 7mm, there is sideplay between wheels and rails, just as there is in 4mm. In 7mm, the coning of wheels also comes into play. On the prototype, this is compensated with sprung suspension, but it highlights a need for some form of compensation in 7mm - if you don't have it, a vehicle can rock due to the wheel tread coning. Assembling on a level glass sheet (using flanges as a means of determining rocking) is a reliable tool, but you do need to check sitting on rails as well.
Just some observational thoughts!
 

·
Registered
Joined
·
2,693 Posts
Some very nice modelling there Graham! It is always interesting to see techniques used on other scales, as they are often very transferrable!
Just to point out that only the first link was for 7mm. The block of links was all 4mm.

I will say that I haven't found much issue with the solebars on kit wagons being overly fragile, although it may be simply that if anything I have had so little experience with RTR I'm not aware of how much tougher they are....! You do raise a good point which I missed off my 'steps' of checking chassis squareness on a flat surface (pane of glass).

One problem I have had on a couple of Cambrian kits was that whilst I successfully assembled them 'square to ground', I ended up with one as a slight parallelogram (i.e. the axleboxes were not quite opposite each other!).
I wouldn't say that W irons are 'overly fragile'. It really depends on the model. RTR W-irons and solebars are a single solid, one piece moulding so consequently, are quite strong. Plastic kits normally have separate solebars to the main chassis/base plate and in 7mm, the W-irons are sometimes separate to the solebars. By definition, parting W-irons attached to solebars which are glued to a base plate runs the risk of splitting the glue join and/or bending the W-irons. Brass kits like your open C of course, are a whole different ball game.
Bottom line is that I recommend that wheels should be fitted at the same time as solebars and W-irons so that it is not necessary to later force the W-irons apart to fit wheels.

Your parallelogram is a classic example of what I mean by checking squareness and the perpendicularity (right angle) of axles to rails. I always use a jewellers metal set-square to check this. In 4mm, it isn't that noticeable if you get it wrong, but in 7mm, you will notice a vehicle 'hunt' - and it looks terrible!

Agreed completely on encouraging tackling kits. They can also teach you a lot about how the prototype functioned.
Agreed absolutely!

Hearing of that issue was one of the reasons why I decided to standardise on Gibson wheels for wagons (also the fact that they look nicer than the Hornby/Dapol/Bachmann wheels!)
I mostly standardised on Romford wheels many years ago (now available from Markits) but I did explore others such as Gibsons, Maygib and Sharman. I used a lot of Gibsons until they started having 'flash' issues on the backs of wheels and then their trueness wasn't perfect. These days, I largely use Hornby wheels for kits (unless they are supplied in the kit) as these are readily available in Australia at a reasonable price. They need gauging out to 14.5mm B2B, but otherwise, are very good.
 

·
Registered
Joined
·
2,693 Posts
Further to which, the coning of the tyres is effective in 4mm. Dapol accidentally supplied the proof by (some dozen years past) putting a batch of wheels with parallel tyres in some of their wagons (the one I particularly recall was the 6 wheel milk tank) which would randomly derail as a result. Changing these wheels for any other conventionally coned tyred wheelset fixed the problem completely.
Yes, I have 6 Dapol milk tankers from the first batch. The wheel treads were dead flat and had no coning at all. They ran really rough! These wagons were the first time I ever had derailments on my layout.
The lack of coning meant that there was no flexibility when crossing pointwork and consequently, they derailed on my Peco code 75 track.
I replaced all of these wheels with Hornby wheels. I seem to recall that I had to swap the axles because the Dapol axles on these wagons weren't a standard length, so the wagons now have Dapol axles with Hornby wheels. But they run really well now without problem:

Just a word on coning on the prototype: its primary purpose is to accomodate the fact that railways wheels are fixed axles and don't have 'differentials'. By moving sideways changes the circumference of the wheel, thereby assisting going around curves. Coning also has the effect that on straight track, flanges are technically not necessary, although for safety reasons, that would never be permitted! On curves, flanges prevent derailments. Be aware that cant on curves is never configured to enable a vehicle to travel in perfect equilibrium. There are several other parameters which also come into play in the calculations including the line speed and curve radius.

These days, there is a further variation: low floor trams which often have split axles. This changes the whole kinematic dynamic behaviour and is usually speed limited for safety reasons.
 

·
Registered
Joined
·
2,693 Posts
Slippery slope time. Some day you'll look at a P4 wheelset...

I was similarly afflicted in my teens, up to this time on a diet of 'Jackson' wheelsets, when the new MGW wheels came supplied with the range of 3H's 4mm injection moulded wagon kits. Polished chrome steel pinpoint axles and matching brass bearings, wheel centres moulded plain or split spoke, solid, Mansell and three hole disc (and there was more, in smaller and larger wheel diameters) turned mild steel tyres. There was an interlude of (club) movement into P4ness, but then for home layouts I decided on OO...
Most of my Jackson/Romford wheels were fitted to my rolling stock in the 1990's. Since then, I have used a bit of a mixture: Ultrascale for locos, Romford/Markits/Gibson/Hornby. All have worked well.
P4 is another ballgame. As a professional permanent-way design engineer, my father went down the P4 route because it was the only way to get exact scale and exact fidelity to the prototype he was designing. This was his layout: Last Trains to Littlehempston - Model Railways On-Line
Over time, the P4 track became unstable and suffered gauge narrowing. It turned out that the plastic used by P4 Track Company shrinks over time. Faced with this problem, the fact that the layout still needed about a dozen turnouts to complete it and the fact that the suppliers P4 track components had basically gone out of business, he had a dilemma: how to complete a layout when the track parts were no longer available and how to fix gauge narrowing issues when replacement parts were no longer available.
It was at this time that he came to the conclusion that P4 is not viable. To be honest, I was never supportive of it. My father ultimately decided to abandon P4 and go to O gauge: Ashburton - Model Railways On-Line
At the time he started the P4, the only RTR available in 7mm was Heljan's Hymek and Dapol's 14xx was on the distant horizon so the 7mm scale RTR that we are blessed with today, hadn't yet eventuated. He often says that if he had the foresight at the time, going 7mm instead of P4 would have been a better choice. I agree.
So our view is that P4 is a waste of time now. Looks very good, but the tolerances are too small to be practicable. If you want that sort of thing, do it in 7mm scale and don't waste your time with P4!
 

·
Registered
Joined
·
2,693 Posts
Whilst a couple of years ago I had some issues with Gibson wheels that were wobbly/had flash/loose tyres, the last couple of batches (~60wheels in all!) I've bought have all been perfectly straight and true! The main 'issue' I have with Hornby wheels is that I dislike the fact that they're shiny silver as supplied, and I'm not keen on painting wheels if I can avoid it...
I believe that there was a period of manufacturing difficulties at Gibson which yielded the problems we have mentioned. I have a whole load of Gibson wheels to fit to Mark 2's and a full-length HST at the moment and every set does appear to be perfect.
As far as 'shiny' wheels go, that has never been an issue for me. Most manufacturers have had non-anodised wheels as some point in history. I paint all my wheels anyway, both inside and outside faces - cameras and flash guns find things that are unpainted!

Is certainly true regarding the 'differential effect' provided by the coning angle around curves. As you've highlighted, it is difficult to configure a curve for perfect equilibrium, particuarly on the mainline where you may have a EMU rocking around at 100mph line speed, and a freight train at 75mph.
The point I was making was that curves and cant are purposely not set up for perfect equilibrium.

Setting of the cant (superelevation to those in NA) is always a bit of a balance for different stock/speeds, and is where some of my PWay colleagues would claim they earn their living! :p Cant deficiency, changes in vehicle bearing, transitions etc all come into it!
That's right. I have an article about all this here: Cantand Transition Design - Model Railways On-Line

I know that this is something I will want to look into properly when I am (eventually...) able to build a layout to run things on, as including proper transitions, cant and 'flowing' track work does greatly improve (in my view) the look of a train running around a layout.
It is properly implemented on my layout here: Ashprington Road - Model Railways On-Line
Even at 5 foot radius, our model curves are right on the bottom end of the tightest permissible prototype curves, scale-wise. In practice, such radii would have a 10mph speed restriction and require someone to walk along side checking for wheels jumping rails. Yet we run HST's round this at top speed!
So what I did was use the minimal transition permissible as described in our cant and transition design article. It is a good idea to use a length at least the length of a bogie coach to allow for twist - we don't have the benefit of flexible suspension on our models. I think for all intents and purposes, the vast majority of modellers should all be using the same transition length because their radii are way off the bottom of the prototype minimum!

That said, I'm not likely to go all the way to P4 standards, but am planning on using OO-SF (i.e. EM-2mm) as the narrower crossing and check gaps do improve running and visuals IMHO (although I appreciate that this is a controversial subject, and it isn't for everyone...)
As I wrote elsewhere, don't bother with P4: the parts supply has dried up so you won't complete a layout.
Please don't use 00-SF. It was something invented by one individual and isn't supported by the trade. It attempts to solve running issues by reducing the track gauge without addressing wheel standards. Considering that OO gauge track is already under-gauge by over 2mm, I can't think of a more silly approach than to reduce the gauge even further!!
If folk have running issues, then they need to address their track AND wheel standards at the same time. And if folk are prepared to go to the effort of building OO-SF track, then they are quite capable of solving the problem properly with properly matched wheel and rail standards. Please don't get sucked into OO-SF - it is nonsense!
Better still, go to O gauge!!!

Happy modelling!
 

·
Registered
Joined
·
2,693 Posts
Watching your modelling brings back happy memories of when I was building large numbers of Ratio and Coopercraft GWR wagon kits back in the late 80's prior to my move to early 1960's BR. I still have all those wagons but none of them have run for 30 years!

Is that open C kit still available ? I think you said it was Ratio ? It looks very similar to the long tube wagon currently made by Bachmann ?
 

·
Registered
Joined
·
2,693 Posts
I think the worst kit of that era that I ever came across was the Parkside Grampus wagon. I think this was one of their first kits, made of a plastic that was so brittle, you couldn't cut parts off sprews without breakage and the plastic wheels seemed to have 12mm B2B - completely under gauge. Later kits were infinitely better.
 
1 - 9 of 9 Posts
Top