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hi everyone I've dicided for my next project to produce an double frame 0-6-0 tender loco using one of the spare hornby
0-4-0T motor

double frame 0-6-0

There is one thing though that I want to find out. Does anyone know if there was any scottish double framed locos? as I want to make the loco scottish themed
 

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QUOTE (steamrailuk @ 24 Jul 2008, 15:06) <{POST_SNAPBACK}>hi everyone I've dicided for my next project to produce an double frame 0-6-0 tender loco using one of the spare hornby
0-4-0T motor

double frame 0-6-0

There is one thing though that I want to find out. Does anyone know if there was any scottish double framed locos? as I want to make the loco scottish themed

After looking at your drawing you are using a tender drive via a worm gear to the drive wheels of the loco, i would have thought a better way would to have the loco driving wheels powered as around curves it could cause drive issues binding in certain spots possibly ?
 

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Discussion Starter · #3 ·
QUOTE (upnick @ 24 Jul 2008, 21:54) <{POST_SNAPBACK}>After looking at your drawing you are using a tender drive via a worm gear to the drive wheels of the loco, i would have thought a better way would to have the loco driving wheels powered as around curves it could cause drive issues binding in certain spots possibly ?
I thought about that but it causes to many problems trying to fit the motor under the boiler. I'm sure that as long as the two sections of the drive shaft are spaced far enough apart in the rubber sleeve i'm thinking of using to connect them and there weighed down enough, it should work.
 

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Discussion Starter · #4 ·
QUOTE (upnick @ 24 Jul 2008, 21:54) <{POST_SNAPBACK}>After looking at your drawing you are using a tender drive via a worm gear to the drive wheels of the loco, i would have thought a better way would to have the loco driving wheels powered as around curves it could cause drive issues binding in certain spots possibly ?
I thought about that but it causes to many problems trying to fit the motor under the boiler. I'm sure that as long as the two sections of the drive shaft are spaced far enough apart in the rubber sleeve i'm thinking of using to connect them and there weighed down enough, it should work.
 

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firstly...why the need for a 'double-framed' locomotive?

surely the actual steam engine chassis layout really isn't relevant......in this case, with the motor in the tender?

however.......for a scottish loco, which perhaps combines both outside and inside loco frames, what about the Allen-designed Goods engines found throughout the Highland Railway system..from the later 1800's, right up to LMS days?

these were of a design type known as the 'CREWE' type....ie although outside cylinders were employed, the cylinder slide bars were combined with an outside frame, leading to a particularly unique appearance.

for a simple model, this design lends itself to simplistic valve gear.......since slide bars, etc are hidden from view.

http://www.lochgormkits.co.uk/html/page_4_locomotives.html

shows a HR Duke class.....but the 2-4-0 Allen Goods engines were what I was particularly thinking of.

http://www.ambaile.org.uk/en/item/photogra...4663&zoom=2

shows a typical example of a very early HR engine....later ones followed a similar design pattern, but more 'updated' fittings, etc...

http://www.ambaile.org.uk/en/item/photogra...4281&zoom=2

again as above.....

regarding tender-mounted motors?

The ideal method is to step-down the driveline from the motor, to lower the driveshaft line.......this reduces the torque reaction effect.also might place the driveshaft below the cab floor.

around curves there ought to be few issues.....after all, this is the sort of drive associated with better quality diesel mechanisms?

the secret is the placing of either the universal joints, or the flexibility of the driveline.

It IS a widely used system [in the past] when small motors were harder to come by.

I also suggest looking at the tender-loco connection.........cantilevering the tender body [and motor] off the back of the loco chassis increases adhesive weight. [ie, the front of the tender chassis is separate from the main tender body, which is supported at its rear on the tender chassis, and at its front, off the loco coupling.]

Your main problem will be the gearbox arrangement.

are you using the O-4-o chassis in some way?

or just a spare motor from one?

whatever, try to maintain as straight a driveline as possible, motor-to- engine gearbox..
 

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Thanks for the info. The reason why I'm using the double frame is because I have a bachman 08 diesel shunter with that wheel design and since having it I've always wanted to build a victorian styled loco with outside frames.

The reason for the tender motor is because i tried to fit it in the front but it was too big so I dicided to move it into the tender but kept it driven in the front to give the loco enough traction.

The locos you have suggested are very nice designs, I may look into building something like those in the future.

Regarding the motor and driveshaft design. I'm only using the motor from the hornby 0-4-0 and its worm gear, possibly also the cog if needed. I was planning to use a rubber sleeve/ tubing to connect the loco and tender drive shafts, a simplistic form of the universal joint and both shafts will be fixed in place to prevent them flexing except at the joint, in the bends.

I will take into consideration the idea of mounting the motor to the front end while its still in the tender but that may just complicate it. The idea of mounting the driveshaft below the footplate I will try if the gears can go low enough.

If i can find all the parts i need to make it work I'll post a more detailed drawing showing the layout of the motor design.
 

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QUOTE (steamrailuk @ 26 Jul 2008, 22:31) <{POST_SNAPBACK}>Thanks for the info. The reason why I'm using the double frame is because I have a bachman 08 diesel shunter with that wheel design and since having it I've always wanted to build a victorian styled loco with outside frames.

The reason for the tender motor is because i tried to fit it in the front but it was too big so I dicided to move it into the tender but kept it driven in the front to give the loco enough traction.

The locos you have suggested are very nice designs, I may look into building something like those in the future.

Regarding the motor and driveshaft design. I'm only using the motor from the hornby 0-4-0 and its worm gear, possibly also the cog if needed. I was planning to use a rubber sleeve/ tubing to connect the loco and tender drive shafts, a simplistic form of the universal joint and both shafts will be fixed in place to prevent them flexing except at the joint, in the bends.

I will take into consideration the idea of mounting the motor to the front end while its still in the tender but that may just complicate it. The idea of mounting the driveshaft below the footplate I will try if the gears can go low enough.

If i can find all the parts i need to make it work I'll post a more detailed drawing showing the layout of the motor design.

***It will work just fine - I'm close to completing several Midland 4F's with exactly that drive system - fine music wire as a driveshaft inset into pure silicone tube. Keep the centre of gravity low and the loco will work well and if you fill the body with lead, it'll pull well also.

Richard
DCCconcepts
 

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Discussion Starter · #8 ·
QUOTE (Richard Johnson @ 26 Jul 2008, 15:49) <{POST_SNAPBACK}>***It will work just fine - I'm close to completing several Midland 4F's with exactly that drive system - fine music wire as a driveshaft inset into pure silicone tube. Keep the centre of gravity low and the loco will work well and if you fill the body with lead, it'll pull well also.

Richard
DCCconcepts
Which one would work fine? the method I'm planning on using or the method you suggested?
 

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I'd suggest they're both much the same?

the material used for the flexible drive tube needs to be able to resist twisting on either shaft....hence the suggestion of 'pure silicon tube'??

rubber might tend to slip after a while.

an idea might be to get both driveshafts [one in loco, 't'uther in tender]....to end roughly above the coupler pivot points....this will eliminate an unwanted driveshaft 'swing' on curves.

the tube then connects both ends......I doubt there will be much of a lengthening effect on bends.

also, if using a tube driveshaft.....permanently couple the engine and tender!! big pain if shaft separates.

if using ball and socket u/j's, then permanency is less of an issue. [these can be had very cheaply, especialy if one hunts out old Mehano diesels at swapsies.] I've made some out of brass tube, and an input shaft from wire, formed into a tee piece.

I've also used coiled spring as found in car/bike speedo cables.....however, on one old electric boxcab I made, [one truck driven, motor at other end]...the spring would wind up as the motor revs rose........when the shaft gripped enough, the wheels spun and it would take off like a rocket...be warned, much fun can be had experimenting.

NorthWest Shortline make/sell nice neoprene U/J's.......
 

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QUOTE (steamrailuk @ 28 Jul 2008, 02:42) <{POST_SNAPBACK}>Which one would work fine? the method I'm planning on using or the method you suggested?

Both - with conditions: Alistair covered it prety well.

The "rubber" part should not be too long or it will twist much a Alistair's spring - only a tiny bit of twist will be bad for drive smoothness. If the shaft is more than a few CM most should be rigid with flexible material only at the UJ positions. You will have to be sensible with radii - such drives are best on larger radii,

Richard
 

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A small can motor mounted on a fold-up multi stage kit gearbox will fit out of sight within small, low boilered prototypes with none of the difficulties of engineering and concealing a driveshaft coupling. Likely to make for a much simpler job.
 

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QUOTE (34C @ 28 Jul 2008, 16:01) <{POST_SNAPBACK}>A small can motor mounted on a fold-up multi stage kit gearbox will fit out of sight within small, low boilered prototypes with none of the difficulties of engineering and concealing a driveshaft coupling. Likely to make for a much simpler job.

*** Yes, but its not always the right answer.

It is much easier to use an acceptable sized motor in EM or P4 as "between the frames" can be utilised better, but not so easy in 16.5mm. Motors get to be too small.

Experience shows that small can motors have little torque and less tolerance for hard work, especially current batch mashimas which run far too hot... space for weight is lost and pulling performance suffers. For harder working loco's not such a good idea...

Its only kitchen table engineering really... there's little difficulty in using a single or 2 stage box and tender driveshaft other than arranging front/rear bearings for the worm on the gearbox, and thats not so hard. Use an NWSL gearbox and its done for you.... Add a little pure silicone aircraft fuel line as the flexible part of the shaft/as replacement for universals and its smooth as silk....

I'd possibly sometimes stay with a loco mounted motor in a whitemetal loco but having built a large number of loco's such as Brasmasters 4F with the beautifully crafted milky bar boiler anything small that does not have a metal body now works better for me with tender drive - its effectively invisible with a close coupled tender anyway, and the ability to use the entire boiler and firebox filled with lead makes a big difference to pulling power on a 4F etc.... A well balanced 0-6-0 will do surprisingly well built this way. Add suspension and pickup improves & pulling power is exceptional!

Richard
 

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in addition, this sort of set-up is actually used quite successfully in the proprietary world.....in most decent diesel models???

all that is being created is effectively a diesel chassis.....with a gear tower of sorts, a driveshaft and u'j's....[ a diesel needs these for truck swing]....and a seperately-mounted motor.

I dont see too many modellers longing for the old days of motor bogies?

Rivarossi used [possibly still do] a similar sort of system to power their UP Big Boy and mallets.

they dont have two motors , each powering a separate engine unit...but had one [big] motor linked to two gear towers by driveshafts and u/j [or flexible joints]....

as Richard says, if the driveline can be ''engineered'' to lie as low as possible, it would be almost invisible.

but, even if not, then a slim driveshaft, even going in to the loco through its firehole, is hardly noticeable.

But if appearances ARE a worry......just take a low down, silhoette view of any of those much-vaunted steamers from Hornby/Bachmann?

See the tender drawbar?

none too realistic, is it?

yet, no-one really worries?

......and if one is onto constructing one's own locos , then at this stage of one's modelling career, one is less likely to have retained set-track curves?

so, as with an expensive etched kit, one considers one's minimum radius??

in the past, such drive systems have been plagued by a lack of easily-used flexible material.....at least, one that didn't have to be replaced at every service......now we have aircraft fuel line, and its ''problem solved?''

also, as Richard says......it allows the use of a decent, meaty motor in a slender loco......rather than something akin to a swiss watch?
 

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just to add to comments regarding pros/cons of tender mounted motors....[as distinct from tender drive...which is something else entirely].....I happened to re-read an article in the last MRJ..[no 183]...a description of a loco kit build...namely, a Dave Bradwell 7mm scale kit for an LNER K1...all singin', all dancin'.....it uses a tender mounted motor, driving a loco gearbox via a driveshaft.

reasons for this drive layout.....[especially considering it's a 7mm scale loco, not exactly small, either]..is the ability to get a decent sized motor, plus a couple of hefty flywheels into what is effectively a wasted space, yet an intrinsic part of the loco.
The flywheels are of such a size that electronic 'mass' really isn't needed.

incidentally..the article states that Branchlines sell a line in U/J's and driveshafts....

the gearbox is a standard High Level item.....and with this set-up, there is one other advantage, and that is, the gearbox can be ''fully floating''...ie with the axle, the axles can then be sprung....all of them.
this is hard to arrange with an integral motor/gearbox unit.....

because space considerations are less, step-down gearing can also be arranged in the tender........
 

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Discussion Starter · #15 ·
I've done some basic measuring and it looks like the driveshaft will be just above the footplate. I've though of a few ideas about what to do with the exposed driveshaft and would like your opinions on which is best or if you have another idea.

Leave it exposed but paint it black to camoflage it

Raise the level of the cab and tender footplate above the driveshaft

Build loco with fully enclosed cab like seen on blanche from the ffestiniog railway, if this design was used on coal fired locos
 

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No dispute that a tender drive transimission can be made to work well. The 'piano wire' drive shaft would be my choice for the prototype proposed, since the mooted design would be of a vintage that would have a very rudimentary cab: little more than the weatherboard, with a metal sheet 2 to 3 feet wide as a roof; and a pretty shallow tender also. But I would only go that route if direct mounting of the motor on the driven chassis proved impossible. If it's a small engine, it doesn't need the 'heroic' traction conferred by a solid lead block oocupying the whole boiler and firebox.QUOTE (alastairq @ 28 Jul 2008, 11:09) <{POST_SNAPBACK}>But if appearances ARE a worry......just take a low down, silhouette view of any of those much-vaunted steamers from Hornby/Bachmann?

See the tender drawbar?

none too realistic, is it?

yet, no-one really worries?
That's a tangent to the original thread, but it is one of the reasons why I much prefer Bachmann's steamers. Their blue riband models have the drawbar correctly positioned in the drag boxes. Detail up with representations of the hoses and it looks good from a trackside eye level view, (the way my layout is set up). Hornby still with one exception use an unrealistic horror: these have to be replaced, the single exception being the new Britannia on which they have done the job right.
 

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QUOTE That's a tangent to the original thread,

not really...simply pointing out what folk find acceptable....since a major argument seems to be one of appearances of the driveshaft?

A simple step-down gearset on the end of the motor shaft would take a driveshaft below footplate level.....

adhesion is an issue...thes old locos were able to pull in real life....otherwise they would have been replaced toot sweet.... or re-built.

Motors tend to be very light in weight, and motor size needs careful thought...as does gearbox layout,if aiming for a built-in power unit.

with a tender-mounted motor size is less of an issue......it also fills a wased space, and allows decent heavy metals to be used within the loco...metals which can be shaped to fit available spaces.....

an issue which needs to be addressed is , how to transfer electrical power from loco chassis to tender?
 

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Discussion Starter · #19 ·
I'll consider the gear step down method for the driveshaft if I can find enough gears to do so.

You brought up how I would collect power from the track to motor. The only methods I can think of will be using one of hornbys methods, running a wire from the loco to the tender. The other is from what I saw on my American Old Timer 4-4-0, collecting power from the tender wheels. The later seems the best option at moment.

I was informed to use silicon tubing for the connection between the two driveshafts, but I don't know where to find it. Does anyone know what type of stores sell silicon tubing small enough "about 1mm inner diameter"?
 

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QUOTE (steamrailuk @ 29 Jul 2008, 22:13) <{POST_SNAPBACK}>I'll consider the gear step down method for the driveshaft if I can find enough gears to do so.

You brought up how I would collect power from the track to motor. The only methods I can think of will be using one of hornbys methods, running a wire from the loco to the tender. The other is from what I saw on my American Old Timer 4-4-0, collecting power from the tender wheels. The later seems the best option at moment.

I was informed to use silicon tubing for the connection between the two driveshafts, but I don't know where to find it. Does anyone know what type of stores sell silicon tubing small enough "about 1mm inner diameter"?

**Actually if you close couple engine and tender and use a music wire driveshaft its pretty well invisible anyway, so above the footplate is OK if thats a lot easier for you..

As stated earlier in this thread, the silicone tube is model aircraft fuel line - you should be able to buy it at any hobby shop that sells R/C aircraft I'd think...thats where I get mine anyway.

Richard
DCCconcepts
 
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