Nick Dunhill's Workshop - JLTRT LMS 10001

Yorkshire Dave

Western Thunderer
Apparently I have a model of 10000 (16, there's the science gags again, come on keep up) to build soon (double-bubble), and each will have one power bogie and one unpowered. This of course makes fitting a decoder a doddle. Each loco can have a Loksound V5 in it, as there's loads of headroom in the decoder's rectifier with only one motor (plus a mini motor for the fan.) I pre assembled all the components of the decoder with a speaker upgrade. I know JLTRT locos often have 2 motors fitted. The motor in this loco is the same as would be fitted inside a pacific steam loco, so I often wonder why a second motor is desirable? Makes fitting a decoder much more difficult.

In an ideal world and if the kit was designed properly it would be arranged for a central motor drive to the trucks via a cardan shaft to provide an all axle (or at least an A1A-A1A) drive - which would be my preference.

As for two powered trucks in diesels - I would hazard a guess this would be more down to weight distribution and traction for haulage capacity.

In a diesel or electric loco the weight is generally evenly distributed along the length of the body. Therefore in a single truck powered model some of weight applies downward forces to the drive truck and some on the trailing truck, ergo the driving truck has to not only pull itself but the 'deadweight' trailing truck as well. The answer is a redistribution of weight towards the driving truck. With two powered trucks or two trucks driven with a centrally mounted motor via cardan shafts the weight distribution issue doesn't arise.

In a pacific steam loco as you've alluded to the wheelbase is a lot longer and the boiler allows for a greater weight to be located above this to provide more traction.

I suppose at the end of the day it's the modellers choice whether they want a single or twin powered truck drive and what the loco will be used to haul.

Having said all that my 7mm Met Bo-Bo has a single truck drive except I used the SDMP/Finney 7 gearboxes and slung the motor within the drive truck. And similarly with my 7mm NER ES1 I have arranged for the outer axles in each truck to be driven by a central motor via cardan shafts and SDMP/Finney 7 gearboxes.
 

richard carr

Western Thunderer
Nick

One motor bogies is perfectly fine to haul prototype length trains. It's far more important to have sufficient weight in the body to ensure adequate traction. I like the ABC supplied 6 watt maxon motors, they run really well with a decoder.

The Loksound version 5s are perfectly adequate to power the motor, however, there isn't a lot of power for sound, so I much prefer the the Loksound V5L with twin speaker outputs. Are you fitting any lights ?

Richard
 

Dave Holt

Western Thunderer
I'm not sure it translates into 7 mm, but my experience with single power bogie 4 mm diesels is that the haulage capacity varied dramatically depending whether the powered bogie was leading or trailing (can't remember which was the better) despite maximum weighting over the drive end. The problem wasn't motor power but traction.
I'd certainly recommend twin power bogies, either with twin motors or central motor with Cardan shaft drive to both bogies.
Dave.
 

Clarence3815

Western Thunderer
Many thanks both.

It was a naughty question as I was thinking of the Merseyside Express which of course would have a Princess equivalent at least up Camden Bank.

The chances of recreating it in 7mm model form on that grade must be very slim, unless anyone knows differently?

Bernard
 

Nick Dunhill

Western Thunderer
This is a interesting conversation. I have a lot more experience of making smaller steam locos, and the customers I build for usually don't expect a 2-4-0T loco from 1880s to pull 12 bogies. It's physically impossible to fit a massive motor in one, so something akin to a 1833 is your best shot. It needs electronics, say a V5, a stay-alive unit and a sugar-cube type speaker, which doesn't leave much room for ballast. I try to shoot for 750g (total mass) and that way the loco will comfortably pull a couple of coaches, as it did in real life.

I suspect the second motor is to pull the mass of lead added to give you the adhesion. Why not look at your stock? A well known modeller I once built a Princess for had coaches that were not very free running (poor/no bearings) and each coach weighed in at around a kilo. Perhaps that could also be part of the problem.

I suspect that there are modellers running 10000/1 in a consist of 4 motors (plus roof fans, hefty speakers, lights etc) needing a small sub-station to supply the amps?

Bernard, here's a Princess I made hauling a massive train up PW's steep hill.


 

simond

Western Thunderer
The Folkestone club 0 gauge track is level, but it's a tiny 4-4-0, with decoder and speaker and as much lead as I could squeeze in. The rolling stock does not have ball bearings, just standard brass. As are most of the coach bodies...


And this was my Duchess before I refitted the valve gear (incorrectly :() on a 1 in 100 on a corner, with 7 bogies and two smaller vehicles. Again, pretty standard garden railway stock, mix of plastic and brass with plain bearings.

 
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OzzyO

Western Thunderer
the Class 50 was only 2700 HP and a type 5 and even they were paired up for the biggest expresses north of Crewe.
Hello Nick, Mickoo,

the class 50 was a type 4 (type 4, 2000 - 2999 hp.). There was two reasons for the twin power units north of Crewe. One was to keep to electric times and acceleration from station stops. Two was in case they got a peg stop on the clime to Shap. One loco could do the job but not the acceleration that was timed for the electric schedule.

ATB

OzzyO.

Ps. Type 5 3000+ HP.
 

OzzyO

Western Thunderer
Hello all,

I'm attaching a snippet from a spotting book, this range of books are normally pretty good with their information.
IMG_0222.JPG
So you can see that the class 50s drop in the type 4 group by their old numbers D400 - 449 and their horsepower.
If HS4000 had been taken into fleet service would the class have been type 6 or 7?

ATB

OzzyO.

PS. sorry Nick about wandering off topic.
Hello Mickoo 10000/1 at 1600 HP puts them in the type 3 range, but not by their numbers the same as the SR ones would just scraped into the type 4 range if my memory is correct.
 

dibateg

Western Thunderer
For diesels, I've always used large scale decoders - LoksoundXL for example with a DCC system that is cable of giving the required current for two motors if required. You'd do that in DC is any case...

Regards
Tony
 
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