0-4-0 saddle tank speeds

[davetheroad]

I am setting up a small Hornby 'smokey joe' 0-4-0  for shuffling mineral wagons about on my layout. I now about all the racing motor issues and they are not a problem as I find that the loco pulling 10 wagons can easily sustain scale speeds through pointwork of 7mph and sometimes 5mph or just over 3mph light engine. The top speed is a scale 21mph and the question is, is this too high?

 

Or putting the question another way does anyone know what the prototypical top speeds of these small industrial locos was, especially when they were doing their prototypical jobs?

[Siberian Snooper]

My experience of riding on 0-4-0s in preservation is as fast as the driver is prepared to hammer it, some drivers are braver than others. I have clung on like grim death when shunting with some of the more adventurous drivers, even with an assorted load approaching a 100 tons.

[Sam Moss]

15mph is ample. I've been on a 0-4-0 at close to 25mph on jointed track and its terrifying!

[34theletterbetweenB&D]

Low 20's mph sounds about right from a theory perspective for a 36" or thereabouts wheel. The Stephenson gear with slide valves imposes limits on engine rate, and then there's the limited steam supply of a small industrial which won't allow sustained high consumption. The very lively action on track as already mentioned above is going to deter most from 'pushing it' too far.

[asmay2002]

As a top speed 21mph isn't too high.  As a rough rule of thumb steam locos topped out at about diameter speed (i.e the usual top speed was roughly the same as the wheel diameter in inches).  Yes, there were locos that could do more than this and others so rough at speed that you wouldn't want to go that fast.  The diesels that replaced them had much more hard and fast limits on top speed (01 - 14mph, 03 - 28mph, 05 - 18mph, 06 - 23 mph, 08 - 20mph, 09- 27mph) but they were doing the same  jobs so should give an indication that a speed in the 20's is about right.  Generally at the top end the diesel shunters were slower than the steam locos they replaced but as most of the work only required low speed they were fine for the job except on things like ECS duties - not a problem for an industrial.

[Horsetan]

That makes me wonder what sort of multi-gear ratio would ideally limit top speed to about a scale 20mph.

[Fat Controller]

And when calculating this, think of the poor souls who drove ex L&Y Pug 51218 from Horwich to Swansea Docks via the Central Wales line in the early 1960s.

[davknigh]

That makes me wonder what sort of multi-gear ratio would ideally limit top speed to about a scale 20mph.

The HighLevel Neilson tank has a bespoke gearbox that is set at 108:1 and is very satisfying to run light or loaded.  I'm sure off the shelf boxes from HighLevel will do much the same.

 

Cheers,

 

David

[Siberian Snooper]

That makes me wonder what sort of multi-gear ratio would ideally limit top speed to about a scale 20mph.

I would suggest using the speed calcultor on the High Level site, it's in the gearbox planner.

[Nearholmer]

There is the question of "top speed", then there is the question of "shunting speed".

 

Shunting, by a well-practised team of driver, fireman, and shunter, can be very nippy indeed, not the slow bumbling that one sees on some model railways. The absolute speeds involved may not be high, but the accelerations and declarations certainly can be.

 

A lever-reverse steam loco is a particularly nippy beast when it comes to changing direction, to the degree where very early (pre-WW1) internal combustion locos, which had ponderous gear-changes, showed-up quite badly against steam in comparative trials.

 

On "top speed", a key determinate of the speed at which a driver will "bottle it" is wheelbase, which is what controls "boxing" or "hunting". An 0-4-0 with a long wheelbase (there were a few) won't "box" much, whereas a very short wheelbase 0-6-0 will. 0-6-0 Dock shunters, like the USA tanks, "box" quite badly.

 

A good place to see some of this is narrow gauge railways, notably the Festiniog, where it is possible to ride behind outside-cylinder four-coupled locos, at speeds that are high relative to wheel diameter and track gauge, and to watch them "box" to quite impressive degrees.

 

K

[davetheroad]

Thanks everyone I will attempt to avoid horrific speeds.

 

Are people suggesting i change the gearing? All there is is a worm gear and an ordinery gear wheel.

 

I am using onboard battery power and a radio receiver to control the loco. The receiver delivers PWM 9V via a step up voltage regulator and I have programmed the receiver with 55% maximum throttle, giving a max of essentially 5V. This results in a nice smooth 21mph. Three quarters throttle gives about 15mph.

 

The controller uses a potentiometer and there is a half throttle indent. As the standard racing motor displays a lot of stiction and not much low speed torque the trick is to by experiment find the minimum throttle setting that starts the loco and 10 wagon train when the controller is set to half throttle. If that looks OK and not too jerky I will be content with that. At the moment the indent setting delivers about 2.5V but I can vary that and I intend to run tests so that I know the train will start under all circumstances.

 

A replacement motor or gearing might be useful as long as it is easy to fit, I have hand tendon problems so anything fiddly is to be avoided.

 

ps - all this started because on another forum someone mentioned it would be difficult to fit BPRC in a 0-4-0 loco so I thought I would try it. I did not have a use for a 0-4-0 on my layout but prototypically there were gypsum mines in the area so I could justify a loco I suppose. This leads on to another question. The era is the early 1950's so what wagons would be used for moving gypsum? I can't find any images on the web.

[Nearholmer]

Judging by what can be seen here https://m.youtube.com/watch?v=_gF5I7qPTuc looks like 16T steel mineral wagons.

 

I was slightly surprised by that, because I wondered if the product was sensitive to rust staining, like China clay.

 

K

[davetheroad]

Brilliant!, thanks for the link, I will be watching that a lot of times

[Quarryscapes]

There was an accident on the Cambrian where an 0-4-0st was attached to a train to provide banking assist and the train engine crew was unaware of the addition, the small tank ending up jumping off the track at approx 45mph

[Fat Controller]

Judging by what can be seen here https://m.youtube.com/watch?v=_gF5I7qPTuc looks like 16T steel mineral wagons.

 

I was slightly surprised by that, because I wondered if the product was sensitive to rust staining, like China clay.

 

K

Sheeted 16-tonners were used for gypsum until the traffic ceaased. I don't think rust-staining was as much of an issue as it was with kaolin; most of the plaster and plaster-board I've ever encountered has had a pink tinge to it. Apart from plaster, the other main use for gypsum has been as an additive during the manufacture of cement.

[davetheroad]

The video also appears to show the use of planked wagons so in the absence of any information on when steel wagons were introduced I might use those as an alternative.

[Nearholmer]

FC

 

I thought the traffic still operated now, and certainly it has been carried in hoppers for many years, as here https://m.youtube.com/watch?v=dVRGnw-pZjE

 

K

[davetheroad]

That's interesting, those hoppers did not have covers! What happens if it rains?

 

question - what would be the best way of representing the loaded gypsum ?

[asmay2002]

That's interesting, those hoppers did not have covers! What happens if it rains?

The gypsum gets a bit wet.  It isn't very soluble.

[Fat Controller]

That's interesting, those hoppers did not have covers! What happens if it rains?

 

question - what would be the best way of representing the loaded gypsum ?

Coarse plaster, perhaps? Mix with water, spread on sheet of clingfilm on work-bench, and when almost dry, break into fairly small pieces.Glue these on to a former of some sort.

[Nearholmer]

It looks pretty much like very, very pale limestone ballast, so you might be able to use a suitable woodland Scenics product, glued onto a also former.

 

K

[alastairq]

Talc?

 

Can make one's trains smell nice too?