Weird steam related question on 2-8-2 wheelbases

[scaro]

Found a 2-8-2 used on logging roads with tiny drivers and I was thinking, since I dabble in TT scale , it might be possible to get something from N chassis wise, as it has 44" drivers which would be 9.3mm diameter. From front - rear axle centre, overall driver wheelbase is only 12 feet, 30.5mm. 

Do any of the N scale 2-8-2s have wheels of this diameter & overall wheelbase ? 

And, critically, a wheel - axle - gear muff arrangement that would allow widening from 9mm to 12mm gage?  I was thinking maybe a Heavy USRA 2-8-2.

With Kato-manufactured Atlas & ConCor diesels, it's not hard to adjust gage, due to the sleeved half axles that slide over the one piece gear-axle. But I don't know that Kato did steam with this kind of setup.

Cheers, Ben

[mmagliaro]

Since you want 44" drivers, 160/120 (convert from TT to N) would imply 58" drivers in N Scale.
The Kato 2-8-2 is more like 63", but that's not too bad a match, and it's a great mechanism.

As for spreading the width to accomodate TT, that's going to be tough, but is actually doable.  On the Kato
Mikado, if you made a longer piece of 1.2mm axle, pressed the drivers and gears off the existing axle and pushed them on your new one, you could pretty easily set up a driver at TT width.  You would have to requarter them all, as there is no alignment to be had once you push the wheels off those steel pins, but it would all work.  I just pulled the drivers off a Kato 2-8-2 driver axle and measured the axle diameter (.047" or 1.2mm).

[scaro]

Thanks for this, it sounds like a mech worth looking at. I'm no expert in steam but the Katos do surface at UK train shows. The Rivarossi 2-8-2 is said to have 60" wheels, but the downsides are pizza cutter flanges, and zamac chassis, if you are unlucky enough to get an old one.  Cheers, Ben

[mmagliaro]

Thanks for this, it sounds like a mech worth looking at. I'm no expert in steam but the Katos do surface at UK train shows. The Rivarossi 2-8-2 is said to have 60" wheels, but the downsides are pizza cutter flanges, and zamac chassis, if you are unlucky enough to get an old one.  Cheers, Ben

They are all "old ones" at this point.  Whether or not the Zamac frame holds up is always a crap shoot.  But at this point, if it's lasted 40+ years without crumbling or warping, it's probably going to be okay.   Spreading the drivers on a Rivarossi engine is going to be far more difficult.  They use a thick brass axle with a brass gear that is all one piece.  You can't just press the gear off and make a new axle.  The pizza cutter flanges are the least of your worries.  Those can be ground off.  But the whole axle/driver attachment on the Rivarossi will be much harder to widen than on the Kato.

[scaro]

Thank! The Kato it is, then.  Oh yeah, what is the spacing between axle centres on the Kato drivers?  The real thing is 12' overall;  4' + 4' + 4'. 

Do you have any views on the Model Power 2-8-2, or Kato's Japanese D51 ?

[peteski]

Thank! The Kato it is, then.  Oh yeah, what is the spacing between axle centres on the Kato drivers?  The real thing is 12' overall;  4' + 4' + 4'. 

Do you have any views on the Model Power 2-8-2, or Kato's Japanese D51 ?

Model Power 2-8-2:  http://spookshow.net/loco/mp282.html
Since the all-metal  shell is an integral part of the mechanism, it would be difficult to use for kitbashes.

[thomasjmdavis]

The Bachmann 2-8-0 Consolidation has closer wheel diameter.  I can't be too precise, because mine is currently together, and it is difficult to get the measurements with a caliper without pulling apart the running gear.  But the wheel diameter is approximately 9.5 mm over the tread, and about 9.6mm over the flange.  About 35mm C to C front to rear axle- bigger than what you  are looking for, but closer than most Mikes.

[draskouasshat]

The newer d51 has smaller drivers but they aren't spoked. They made an older version that had spokes but I'm not sure on the driver diameter.

Drasko

[mmagliaro]

The Bachmann 2-8-0 Consolidation has closer wheel diameter.  I can't be too precise, because mine is currently together, and it is difficult to get the measurements with a caliper without pulling apart the running gear.  But the wheel diameter is approximately 9.5 mm over the tread, and about 9.6mm over the flange.  About 35mm C to C front to rear axle- bigger than what you  are looking for, but closer than most Mikes.

I agree the dimensions are closer, and I believe the Bachmann engine's drivers should come apart the same way as the Kato.  But those drivers... .those NON-see-through spokes!  Ugh.  If I were going to harvest drivers from somewhere, I'd live with the larger diameter of the Kato in exchange for nicer looking wheels.

[scaro]

What's the overall wheelbase of  the Kato, front driver centre axle to rear? 

Thinking niceness of the wheel may matter less, if wheelbase is 10mm too long.

[mmagliaro]

What's the overall wheelbase of  the Kato, front driver centre axle to rear? 

Thinking niceness of the wheel may matter less, if wheelbase is 10mm too long.

1.31" which is 33.32 mm  or  a TT scale 13.1 feet.  It's a foot over, but the Bachmann 2-8-0 is even longer.
I was kind of surprised by this.  I always thought the Bachmann 2-8-0 had a shorter wheelbase than the Kato
Mikado, but it doesn't. The Mikado is a hair shorter.

Then this made me remember the Life-Like 0-8-0 switcher!   Wheelbase is  11.4 feet in TT scale.
Driver diameter is 57" in N = 42.75" in TT.   This is the closest match to what you are trying to build yet.
It's not as easy to find a LL 0-8-0, and they are not as good a running engine as the Kato Mikado, but they can be made to run superbly with some tweaking and weight.  You should be able to do the same thing with the 0-8-0: make new axles and widen the gauge.

[scaro]

Oh, nice one. I'll have a hunt for the 0-8-0.

Puzzles me that the Bachmann 2-8-0 is a longer wheelbase than the 2-8-2 too.

cheers, Ben

[narrowminded]

... Spreading the drivers on a Rivarossi engine is going to be far more difficult.  They use a thick brass axle with a brass gear that is all one piece.  You can't just press the gear off and make a new axle.  The pizza cutter flanges are the least of your worries.  Those can be ground off.  But the whole axle/driver attachment on the Rivarossi will be much harder to widen than on the Kato.

Nothing to add to the general design advice here but will suggest that the gear/ axle issue that @mmagliaro identified would be relatively easy for me to address.  Bore the gear out and replace the axle, any length needed.   The idea is pretty obvious but the execution requires pretty precise tolerance, especially runout, and takes the right tooling for the lathe used to assure a good result.  I could do this if the only stumbling block in an otherwise good choice would be this gear/ axle issue.  It would not be a major job for my equipment.

[thomasjmdavis]

1.31" which is 33.32 mm  or  a TT scale 13.1 feet.  It's a foot over, but the Bachmann 2-8-0 is even longer.
I was kind of surprised by this.  I always thought the Bachmann 2-8-0 had a shorter wheelbase than the Kato
Mikado, but it doesn't. The Mikado is a hair shorter.

Then this made me remember the Life-Like 0-8-0 switcher!   Wheelbase is  11.4 feet in TT scale.
Driver diameter is 57" in N = 42.75" in TT.   This is the closest match to what you are trying to build yet.
It's not as easy to find a LL 0-8-0, and they are not as good a running engine as the Kato Mikado, but they can be made to run superbly with some tweaking and weight.  You should be able to do the same thing with the 0-8-0: make new axles and widen the gauge.

Wow, the Kato Mike wheelbase IS a bit shorter than the Bachmann 2-8-0.  And given the undersizing of N scale drivers, the Mike's wheel diameter is only very fractionally different.

Life Like made several nice steam locos.  I wonder if any of the tooling made it to Atlas.

[mmagliaro]

Nothing to add to the general design advice here but will suggest that the gear/ axle issue that @mmagliaro identified would be relatively easy for me to address.  Bore the gear out and replace the axle, any length needed.   The idea is pretty obvious but the execution requires pretty precise tolerance, especially runout, and takes the right tooling for the lathe used to assure a good result.  I could do this if the only stumbling block in an otherwise good choice would be this gear/ axle issue.  It would not be a major job for my equipment.

I have no doubt that you are up to the task of doing this.  But I was really trying to stick to something that would be a lot more straightforward for the OP to implement.  With the other engines, one just has to cut a piece of steel rod for the new axle and push everything onto it.