The limited haulage capacity of modern RTR models

[rockershovel]

I suppose that’s why the Hornby Dublo 2-6-4T was such a popular, hard-working, hard-pulling loco; heavier than a 4-6-0 with the centre of balance pretty much over the centre drivers

[jjb1970]

A question I've often asked myself is to what extent these models are designed? I don't mean in terms of fidelity to prototype and making a mechanism go inside the model, but there are some pretty basic aspects of weight distribution, motor performance and gearing for which calculations can almost be done on the back of an envelope which don't seem to be considered in some cases.

[Middlesea John]

We used a mixture of RTR locos on our new layout "Ladycross" at the Hull show last November.  For express trains we had Hornby Rebuilt Merchant Navy; Original and Rebuilt West Country / Battle of Britain; King Arthur and Schools (current and tender drive) and Bachmann Lord Nelson and Standard Class 5s.  Also Hornby Grange and Bachmann Hall.  All managed 10 coach trains with no problem.  Maybe it's just that we are using larger radius curves but we just didn't have any problems with pulllng power.  

[The Johnster]

Metal bodies are obviously better in terms of weight distribution and haulage, but there are other considerations for an RTR manufacturer.  If there is fine detail to be incorporated, washout plugs, boiler bands, etc, it is far easier to mould it in plastic if a sharply defined shape is required.  This is why locomotive bodies have been plastic since the time that Triang proved superior in detail to Hornby Dublo and forced them to adopt plastic bodies.  CAD and better materials have increased the lead over cast metal bodies, and the modern demand for detail will not allow a return to the old Hornby Dublo standards of crudity.  The answer from the manufacturers' point of view is to make the bodies plastic and cram as much ballast in as can be arranged; the need to provide room for DCC circuitry is a retrograde step in this sense.  

 

I have managed to cram more ballast in to all of my locos than the manufacturers can, and increased haulage capacity and improved running into the bargain, but what I can achieve at home may not be reliably achievable on a factory assembly line where speed of assembly is a factor.  I can increase the weight of my locos with metal domes and chimneys as well.

[Suzie]

The space allowed for a modern sound decoder with a PluX-16 connector (typically would be found in small 00/H0 or N locos) by my calculations is the equivalent of about 30g of lead, or 20g of steel. Does this make a sizeable difference to the weight? I guess that the space for a speaker might make a bigger difference and the PCB with the connector on it will be a bit lighter than the weight it replaces by 5g or so too.

[34theletterbetweenB&D]

Metal bodies are obviously better in terms of weight distribution and haulage, but there are other considerations for an RTR manufacturer.  If there is fine detail to be incorporated, washout plugs, boiler bands, etc, it is far easier to mould it in plastic if a sharply defined shape is required. This is why locomotive bodies have been plastic since the time that Triang proved superior in detail to Hornby Dublo and forced them to adopt plastic bodies.  CAD and better materials have increased the lead over cast metal bodies,

 When the chance avails, take a look at Hornby's B12/3. The entire boiler and footplate is a casting. It does not lose anything to a plastic moulded body. Excellent traction for a class 4P 4-6-0 as a result, not requiring the all too frequent lead stuffing antics I so often have to resort to.

[jimwal]

I now have embarrassingly heavy locos as Tony Wright discovered recently. Growing up on Hornby Dublo, layouts with gradients and wanting decent length trains soon made me realize weight was the answer!

 

Things have moved on, I now have a flat layout on which a 60 wagon coal empties train can be hauled by most any of the RTR 0-6-0 locos.

[rockershovel]

I hardly think that Tri-Ang “forced Hornby to convert to plastic bodies by being superior in detail”, more like that cost was the reason. Tri-Ang were always markedly cheaper than Hornby Dublo.

 

There was discussion of that once-popular stalwart, the Tri-Ang 4F, a little while ago and I don’t remember THAT as being highly detailed, just a clean outline at the right price. The solid, wide-tread, sintered wheels alone were greatly inferior to Hornby Dublo in appearance.

 

Tri-Ang sold large numbers of the “Nellie” series with its unrealistic proportions and unidentifiable prototype; the inside-framed diesel shunter would be another example. The Brush A1A-A1A was a very nice piece, but that came after Dublo’s demise.

[bike2steam]

I hardly think that Tri-Ang “forced Hornby to convert to plastic bodies by being superior in detail”, more like that cost was the reason. Tri-Ang were always markedly cheaper than Hornby Dublo.

 

There was discussion of that once-popular stalwart, the Tri-Ang 4F, a little while ago and I don’t remember THAT as being highly detailed, just a clean outline at the right price. The solid, wide-tread, sintered wheels alone were greatly inferior to Hornby Dublo in appearance.

 

Tri-Ang sold large numbers of the “Nellie” series with its unrealistic proportions and unidentifiable prototype; the inside-framed diesel shunter would be another example. The Brush A1A-A1A was a very nice piece, but that came after Dublo’s demise.

 

Do you mean 3F ??

In the late 50's/early 60's the price for a large HD loco was similar to half the average weekly wage, and some whinge about prices today - oh hang on, HD finished early 60's !!

[rockershovel]

Do you mean 3F ??

In the late 50's/early 60's the price for a large HD loco was similar to half the average weekly wage, and some whinge about prices today - oh hang on, HD finished early 60's !!

...oh ok, we did all this on another thread. The Tri-Ang 0-6-0....

 

I'm unclear what point you are making. Tri-Ang undersold Hornby Dublin by a considerable margin, forcing them to follow suit, although it didn't save them..

Edited June 9, 2018 by rockershovel

[The Johnster]

Triang were considered a very lo-fi attempt when they first entered the market back in the Rovex period with the Black Princess and 'representative' Stanier coaches, but very rapidly established themselves with the Jinty.  They undoubtedly forced HD to at least offer a 2 rail alternative, though 3 rail was never completely abandoned because of it's ability to simplify the wiring of a layout.  The Brush Type 2 was introduced well before Hornby Dublo ceased trading, and was very close to a scale model; only HD's EE type 1 was comparable.  Hornby Dublo could not compete on price, though their mechanisms were of a much higher quality and valve gears especially were of much finer appearance.

 

Both concerns persisted with under scale length models for far too long, and Triang's scale length mk1s were only inferior to Kitmasters when they were introduced.  The sad truth is that Hornby Dublo, having done pioneering work in the late 30s, never really adapted to post war conditions and held on to 3-rail far too long.  Triang and it's plastic based 2 rail concept was the root of pretty much all modern UK RTR, and while they produced some abominations even by the standards of those days, we should acknowledge our debt to them.

 

The 'Nellie/Polly' etc. is a not unreasonable attempt at an NER 0-4-0 tank, let down by the Scalextric drive train.

[sandwich station]

The 'Nellie/Polly' etc. is a not unreasonable attempt at an NER 0-4-0 tank, let down by the Scalextric drive train.

In Triang/Triang Hornby days, they had X04's in them.

[Flying Pig]

 

The 'Nellie/Polly' etc. is a not unreasonable attempt at an NER 0-4-0 tank, let down by the Scalextric drive train.

I know it's a long way from Cardiff to Darlington and there are houses in between, but Nellie is nothing like an NER loco. More like something neither of the Drummonds built, possibly not for either of the South Westerns. Discussed at length in other threads.

 

Anyway, in my day, it was proper Triang-Hornby with Magnadhesion and 1 in 15 was no problem. The locos never slipped back because the loose track pins adhering to the chassis would dig into the sleepers and prevent it.

[sandwich station]

When the chance avails, take a look at Hornby's B12/3. The entire boiler and footplate is a casting. It does not lose anything to a plastic moulded body. Excellent traction for a class 4P 4-6-0 as a result, not requiring the all too frequent lead stuffing antics I so often have to resort to.

I believe that Triang did use plastic for bodies because the detail was superior to metal way back then but things have evolved in the last 50 years or so and the new B12 looks superb.

[Trog]

There is no substitute for weight.

 

Ray

 

Except perhaps steel rails.

 

I had a layout with a 1 in 37 4th radius spiral laid with steel rail track, the spiral was slightly oval and the top level had a nickel silver crossover in the straight section. Locos that had happily made their way up through the lower curves would sometimes slip to a stand on the points. Even though being a short straight that should have been an area of slightly reduced rolling resistance.

 

Although weight and high friction rail would of course be even better.

[jjb1970]

Plastic is good for detail and suppressing cost. If you have deep pockets then I tend to think that brass is still probably the best option.

[The Johnster]

But probably not for a mass produced item.  Triang were part of Lines Brothers, whose expertise was very much in plastic mouldings, originally for household items such as polythene bowls and buckets.  Bearing in mind that they considered themselves to be in the toy train set business, some of what they achieved was remarkable for it's time.  The original Rovex Black Princess had backhead detail, and mouldings for the likes of the Southern Utility Van, with opening doors, and the shortie clerestories was remarkable.  Underframe detail on the mk1 coaches was very good, with crisply moulded bogies even on the 8 inch coaches.  All this looks very crude nowadays, but so does the cast Hornby Dublo efforts that pre-dated it's conversion to plastic.  Even with plastic bodies, HD continued with crude cast chassis, as did Wrenn and Dapol with the items they continued to market.

[Buhar]

Plastic is good for detail and suppressing cost. If you have deep pockets then I tend to think that brass is still probably the best option.

 

But brass construction doesn't contribute to adhesion and thereby haulage, although it tends to leave a fair bit of room for lead.

[newbryford]

Except perhaps steel rails.

 

I had a layout with a 1 in 37 4th radius spiral laid with steel rail track, the spiral was slightly oval and the top level had a nickel silver crossover in the straight section. Locos that had happily made their way up through the lower curves would sometimes slip to a stand on the points. Even though being a short straight that should have been an area of slightly reduced rolling resistance.

 

Although weight and high friction rail would of course be even better.

 

Steel rail (and steel wheels) have much more grip than nickel silver.

 

Going back to an earlier point regarding locos getting better over time - that will probably be because the wheel tread is wearing.

Hornby locos with chrome plated wheels were notorious for being slippy but much better when the plating wore off (although they di require more frequent cleaning.

 

Cheers,

Mick

[The Johnster]

As were Mainline's.  Steel wheels on steel rails are in many ways an ideal solution as well as the most prototypical one, except that they rust...

[jimwal]

Rusty steel wheels and rail on the real railway lead to slipping, on the model rust results in poor electrical pick up and the rust scales are overscale!

[Talltim]

You’re all buying the wrong sorts of locos...

[34theletterbetweenB&D]

Rusty steel wheels and rail on the real railway lead to slipping, on the model rust results in poor electrical pick up and the rust scales are overscale!

 While all steel wheels and rails would be good for traction, surface corrosion is a problem in the UK climate. I have a good number of MGW wheelsets on locos, wagons and coaches dating from forty years past. Mild steel tyres on these. During the twenty five years of idleness between phases one and two of railway modelling they corroded very nicely and look more realistic than any painted on rust! The tyre contact strips polish up nicely with running, but a few months not operating, and oh dear the rust is back.

 

On three locos these wheels are used for pick up, and two of them only get operated irregularly. When they come out to play the first twenty minutes of less than wonderful pick up have to be overcome by whanging them around the test circuit first. So it's very regular operation if going all steel in my opinion. For all its far inferior coefficient of friction, nickel silver is the better choice in our climate.

[The Johnster]

I have the impression, though no direct knowledge to back it up, that pickup is much improved on a railway which is used regularly, ideally on a daily basis.  This seems to allow a degree of self cleaning to take place, and track or loco cleaning is a much less frequent necessity, about once a month in my case.  

 

I have recently acquired a Lima 94xx for a Bachmann chassis conversion, and, just for the hell of it, put it on the track to see if it would go.  It had been unused for lord knows how long!  It started, roughly, with a bit of a push, but within a few minutes of running up and down was running as smoothly and quietly as it probably ever had, though admittedly this is not particularly smooth or quiet.  Wheel treads and backs were not clean, and I might have got it to run even better with a bit of effort, but didn't see the point!

[Suzie]

Nickel silver track in tunnels appears to remain clean, but when exposed needs some cleaning after a long period of idleness, and I guess the same is true of wheels. I find it takes about two days of running to get the track, wheels and pickups operating at their optimum performance - just in time to pack up after a 2-day show!