The Rigid Chassis Debate -

Re:The Rigid Chassis Debate - on Mel's behalf

cheeky that's fair enough. If I said that to the other half I may end up with a black eye....

And leave my pivot out of it people!
 
Re:The Rigid Chassis Debate - on Mel's behalf

Ok Mels said it is a good loco and will run but not quite to the standard he expects. Initially his was tighter than mine and required more running in to loosen things up. I also identified that my gearbox was very tight and as a consequence got very hot. It has required more running in, cleaning and re-lubrication than any Bachmann or LGB model would usually require but this was in line with running in for a live steam loco, on which it is based. Now the choice of motor seems ok as it's not heavy on current and quite happy on an ESU chips output, the weakest point here is the flexible tube connector to the gearbox. I assume this was chosen as they are quieter and cheaper than a universal joint and should be easy enough to replace if it goes. The excessive heat generated in the gearbox was a concern here which is why I've removed it's cover twice and cleaned it now as the gears bed in.
As I see it with my model introducing compensation would be difficult with the flangeless centre axle so simply springing the front or rear axle with minimal travel above and below datum height would probably be easiest. Minimal travel is all we could allow to stop the flangeless driver dropping off the side and causing a forced derailment. Now the flangeless centre axle is essential to get round R1 or R3 so we would have to live with that. These modifications would address the problem with a long wheelbase launching itself of the track if a joint is peaked as happened with many Caledonias too.
The contact issue is the most glaring mistake with a long fixed wheelbase as it was inevitable on anything but a totally flat line that it would rock over a joint or two and cause a stutter, simply using another lair of plungers would have sorted this for another 5-10 pounds. Interestingly on Camberwick and Klien Arosa we have screwed down the frogs on R3 points as we found they make the LGB four wheel logos run better without stalling, despite their skates.
So what would be the ideal for a long rigid chassis capable of satisfying G and 16mm modellers?
I think we would have to follow the flangeless centre driver rather than articulate the rear axle in a limited way as would significantly raise prices and mean widening the frames further to allow it, this in turn causes problems with moving out the valve gear within gauge.
Limited springing on front or rear axle to improve track holding on curves with minor dips or peaks at joints, this also enables maximum traction with all wheels in contact. Single axle drive and relying on the rods to drive the outer axles is fine on hundreds of models and again cheaper and quieter than geared options. Proper quartering is all it relies on with propey bushed bearings with tight tolerances.
Now the bit I'd change, a spur gear drive, like portescap use, that allows the drive to run on and doesn't transfer every motor glitch to a stutter.
 
Re:The Rigid Chassis Debate - on Mel's behalf

Simply a small screw or a nail in the sleepers nearest the frog, in front or beyond, where the converging rails meet the frog. Neil found it was raising up and causing the Tm2/2 to stutter as it rocked over it. I followed his example due to Cale's long wheelbase.
In the garden the same could be achieved by having a strip of preserved wood screwed to the bottom of the point and hidden in the ballast.
 
Re:The Rigid Chassis Debate - on Mel's behalf

hornbeam said:
What gearbox did u use on your loco?

I knew there was a question in here that I hadn't answered :onphone:

ABC Gears gearbox - they specially mounted it onto the Buhler motor, as it's a three point fixing. :thumbup::thumbup:
 
Re:The Rigid Chassis Debate - on Mel's behalf

Now here's an interesting thing ............ maybe .............. I hope :bigsmile:.

As many of you will be aware by now, having sold The Earl I "re-invested" the funds in a second hand gauge 3 (G64) GWR pannier tank built from a GRS kit. Not strictly G scale I suppose, but I will try and post some better pics in the next day or two.

0bb08f87cef14b0cbc6f75a389623229.jpg


Anyhoo, today I had reason to turn this beast upside down for a sneeky peeky at it's working and here's what I found. The resin body (with white metal detailing parts) is attached to a very solid steel and brass chassis (not too unlike the Earl's chassis), onto which is a VERY solid mounting for the very beefy looking Mabuchi motor and brass gearbox. This gearbox drives the third axle .......... and here's where the difference comes with the Accucraft way of doing things ......... which is the only axle which is rigidly mounted. Axles one and two both have a little sideways movement, but they are also able to move up and down by the simple means that their bearing mounts are attached to the chassis by means of a slide. A very simple pivotted arm is attached to each of these sliding bearings so that, if one axle drops, the other is raised (if that makes sense?). All of this means that the loco sits square and true on the track, but is able to cope easily with the kind of undulations that are inevitable with a garden railway. Of course, plunger pick-ups are provided for ALL six wheels - no brainer that one really :bigsmile:.

59564fcfab754c4aa11ac7abbe925309.jpg


Now my standard gauge track currently runs to an 8' long, straight siding, so I can't really comment on how this loco would work on a "proper" layout (although I'm pretty confident that it will run very nicely). BUT the point is that here we have a 6 coupled loco fitted with a compensated chassis who's construction is so simple that it can be bolted together in the home workshop. Not only that, but it has been designed, commissioned and built, not by some major manufacturer with large resources and foreign build facilities, but by a group of enthusiastic model makers who run a shop!!

And the price for this fantasticly simple and yet effective piece of model engineering? Currently available via the GRS website at £658.73 for the complete kit including Slaters wheels, motor and gearbox etc.

I guess that the point I'm making is that not only is it possible to engineer a chassis that is well suited to the rough and tumble of an electrically powered garden railway, but that you don't need a massive amount of facilities or investment in order to do so within a reasonable budget .......... All that you DO need is to know what you're doing. :bigsmile:
 
Re:The Rigid Chassis Debate - on Mel's behalf

Sounds like it's a simple compensated system Mel, and it looks great... When do we see it out at Wetton?
 
Re:The Rigid Chassis Debate - on Mel's behalf

jameshilton said:
Sounds like it's a simple compensated system Mel, and it looks great... When do we see it out at Wetton?
Never James - the standard gauge is at Gooey :bigsmile:.

I'll try and get some better pics in the next couple of days as the forecast is pretty good.
 
Re:The Rigid Chassis Debate - on Mel's behalf

yb281 said:
Now here's an interesting thing ............ maybe .............. I hope :bigsmile:.

As many of you will be aware by now, having sold The Earl I "re-invested" the funds in a second hand gauge 3 (G64) GWR pannier tank built from a GRS kit. Not strictly G scale I suppose, but I will try and post some better pics in the next day or two.

images


Anyhoo, today I had reason to turn this beast upside down for a sneeky peeky at it's working and here's what I found. The resin body (with white metal detailing parts) is attached to a very solid steel and brass chassis (not too unlike the Earl's chassis), onto which is a VERY solid mounting for the very beefy looking Mabuchi motor and brass gearbox. This gearbox drives the third axle .......... and here's where the difference comes with the Accucraft way of doing things ......... which is the only axle which is rigidly mounted. Axles one and two both have a little sideways movement, but they are also able to move up and down by the simple means that their bearing mounts are attached to the chassis by means of a slide. A very simple pivotted arm is attached to each of these sliding bearings so that, if one axle drops, the other is raised (if that makes sense?). All of this means that the loco sits square and true on the track, but is able to cope easily with the kind of undulations that are inevitable with a garden railway. Of course, plunger pick-ups are provided for ALL six wheels - no brainer that one really :bigsmile:.

images


Now my standard gauge track currently runs to an 8' long, straight siding, so I can't really comment on how this loco would work on a "proper" layout (although I'm pretty confident that it will run very nicely). BUT the point is that here we have a 6 coupled loco fitted with a compensated chassis who's construction is so simple that it can be bolted together in the home workshop. Not only that, but it has been designed, commissioned and built, not by some major manufacturer with large resources and foreign build facilities, but by a group of enthusiastic model makers who run a shop!!

And the price for this fantasticly simple and yet effective piece of model engineering? Currently available via the GRS website at £658.73 for the complete kit including Slaters wheels, motor and gearbox etc.

I guess that the point I'm making is that not only is it possible to engineer a chassis that is well suited to the rough and tumble of an electrically powered garden railway, but that you don't need a massive amount of facilities or investment in order to do so within a reasonable budget .......... All that you DO need is to know what you're doing. :bigsmile:

Seeeemples. :thumbup::thumbup::thumbup:
I haven't had an entirely straightforward ride with the people at GRS, but a lot of their stuff is well engineered.

And, as you say Mel, if GRS can do it, why can't Accucraft? I must admit, I would have expected it on something like The Ear. I could have forgiven them on the early, less expensive Caledonias, but they really do need to be thinking that way :onphone::onphone:
 
Re:The Rigid Chassis Debate - on Mel's behalf

Rhinochugger said:
I haven't had an entirely straightforward ride with the people at GRS, but a lot of their stuff is well engineered.
Yes, same here mate. Some of my experiences have also been ....... errrrrr ........ inconsistent, but they do seem to have a grasp of garden railway engineering and make a load of stuff that no-one else does.
 
Re:The Rigid Chassis Debate - on Mel's behalf

Countess/Earl is a good basic Loco but let down by motor/gearbox and rigid fixed chassis arrangements:@

Very unfortunate... so I may have to reconsider if I will proceed with my order for a re-tooled Baguley as it looks very similar :(
 
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