0-6-0 tank locos and compensation/springing

[Kenton]

If not using DCC, does anyone still use those track cleaners made by Relco, etc?

 

Its tempting - like a red rag to a bull, but don't get me started .... Second only to track pins and track rubbers abraders ... a favourite hobby horse.

[chaz]

I haven't cleaned my track for a while now and everything runs better than when I used to clean it before every running session. All I do now is rub a graphite stick over the rail tops now and again.

 

I tried it and it works brilliantly, Dave. But I had to stop using it. My layout includes a short but quite steep gradient and the locos that previously went up it quite happily were just slipping to a stand at the start of the gradient. Graphite is a lubricant....

 

Chaz

[MarkC]

A 4-4-0 is a good proposition for beam compensation, Mark. The 0-4-4T is the tricky one. It can be done but the problem is that the driven axle is usually No 2. I did once see some 2mm finescale LSWR O2 tanks that had been built as if they had two bogies. The ran beautifully and you couldn't tell that the driving axles weren't fixed in line.

 

Chaz

 

Thanks for that, Chaz. I built a Jidenco/Falcon Brass Kirtley 0-4-4WT about 10 years ago with the supplied 'fixed' chassis, and it does look and run well, but I think I was lucky with the balancing etc. Similarly with a Craftsman Johnson 0-4-4T; there I had to fill the boiler with lead to balance it, although the end result is again pleasing.

 

I have been wondering about this idea of a sort of '2 bogie' arrangement; if nothing else, as was pointed out, it does help with the 'throw' of the rear on corners. Food for thought, as it were

 

Cheers

Mark

[chaz]

Thanks for that, Chaz. I built a Jidenco/Falcon Brass Kirtley 0-4-4WT about 10 years ago with the supplied 'fixed' chassis, and it does look and run well, but I think I was lucky with the balancing etc. Similarly with a Craftsman Johnson 0-4-4T; there I had to fill the boiler with lead to balance it, although the end result is again pleasing.

 

I have been wondering about this idea of a sort of '2 bogie' arrangement; if nothing else, as was pointed out, it does help with the 'throw' of the rear on corners. Food for thought, as it were

 

Cheers

Mark

 

It shouldn't prove too difficult - if it can be done in 2mmFS! The bogie is easy, just do what you would normally do. The driving wheels? I would suggest an upward extension of the frames, sufficiently tall to just clear whatever motor and gearbox is used. A cross piece fixed to the extensions would give a place for a bogie pivot. A second framework fixed to the chassis proper would allow the body to be removed leaving all the "gubbins" (good technical word, that) behind. You could incorporate an element of compensation on either or both of the two bogies providing you arranged the scheme so that the loco is kept upright and level.

Disadvantages? Well you are going to have to do quite a bit of work yourself - a kit (however good) is just not going to make any provision for this sort of malarky! The other black mark is that it could be tricky to disguise the fact that the frames are articulated. You would have to balance the need for free movement with the desire to avoid a gap that shows. If your prototype has a set of footsteps, or a sandbox etc it might offer the chance to mask the join.

 

There are other ways of compensating an 0-4-4T but it is notorious as the most difficult case.

 

Chaz

[John_Hughes]

A pair of bogies for an 0-4-4T? Fairlie's Patent, and it works brilliantly in the prototype as well!

[MarkC]

It shouldn't prove too difficult - if it can be done in 2mmFS! The bogie is easy, just do what you would normally do. The driving wheels? I would suggest an upward extension of the frames, sufficiently tall to just clear whatever motor and gearbox is used. A cross piece fixed to the extensions would give a place for a bogie pivot. A second framework fixed to the chassis proper would allow the body to be removed leaving all the "gubbins" (good technical word, that) behind. You could incorporate an element of compensation on either or both of the two bogies providing you arranged the scheme so that the loco is kept upright and level.

Disadvantages? Well you are going to have to do quite a bit of work yourself - a kit (however good) is just not going to make any provision for this sort of malarky! The other black mark is that it could be tricky to disguise the fact that the frames are articulated. You would have to balance the need for free movement with the desire to avoid a gap that shows. If your prototype has a set of footsteps, or a sandbox etc it might offer the chance to mask the join.

 

There are other ways of compensating an 0-4-4T but it is notorious as the most difficult case.

 

Chaz

 

I'm very tempted to try this - will have a good look at the Craftsman kit that's sitting waiting to be built

 

Mark

[chaz]

I'm very tempted to try this - will have a good look at the Craftsman kit that's sitting waiting to be built

 

Mark

 

If you do Mark be sure to post an account of how it goes. I, for one, would be most interested to see how you get on.

 

Chaz

[JeffP]

Its tempting - like a red rag to a bull, but don't get me started .... Second only to track pins and track rubbers abraders ... a favourite hobby horse.

 

Now I have to know.......

[chaz]

Now I have to know.......

 

Shhhhhhhhhhhhhhhhhhhhhh........

[Kenton]

Now I have to know.......

 

No honestly, you don't - and I suspect the rest of the forum will not forgive you... a search for Relco on the forum should bring up this favourite stamping ground in relation to "clean track" ... all you need to think of is "tar".

[JeffP]

Ok, ta.... ....I'll do a search.

[Mike Boucher]

Kenton, if you have found a way to clean the wheels of a loco while it's still on the track - please PLEASE PLEASE tell us how..... waiting here on the edge of my seat......

 

If Kenton doesn't mind, I can answer that...

 

Caveat #1 - this requires pickup on multiple wheelsets/trucks.

Caveat #2 - it doesn't clean non-driven wheels (pilot/trailing or idler wheelsets)

 

Step 1: Get a paper towel, and lay it down over the track.

Step 2: Wet said paper towel with your favorite wheel cleaning solution. (I use "Goo Gone"). Make sure its wet right up to the edge.

Step 3: Put loco on track.

Step 4: Hold on to loco while cranking the power up to 11. Hold it so the wheels slip on the rails.

Step 5: Still holding on, slide the loco so some of the driven wheels are on the paper towel, and others are still in contact with the "bare rail" (for current pick up), and slide it back and forth.

Step 6: Watch two black lines appear on paper towel, as the dirt comes off the wheels and onto the paper towel. Slide the loco back, and slightly move the paper towel and repeat step 5 until you're not seeing black lines appear

Step 7: Get a clean, dry paper towel and repeat to dry the wheelsets.

Step 8. Turn off power, and move the wet paper towel to the other side of the loco. (or use the 0-5-0 switcher to point the loco in the opposite direction)

Step 9: repeat steps 4 thru 8, cleaning the remainder of the driven wheels.

 

Its easier to do than it is to explain.

 

You'll be amazed at how much dirt you pull off the wheels. I've done it with both N scale and O scale locos.

[chaz]

Brilliant, full marks, I will try it out....

[JeffB]

Here's three photos of a compensated 0-6-0 chassis I'm working on for a friend... It's 9mm gauge/HOn30 and will have a 50:1 gearbox with a Mashima 1220 motor when it is complete. It's built up from laser cut brass and steel parts, steel turnings, etc...

 

I can build the same chassis down to 5.26mm gauge, using fine scale wheels, with a slightly narrower gearbox.

 

 

 

 

JeffB

[t-b-g]

Thanks for that, Chaz. I built a Jidenco/Falcon Brass Kirtley 0-4-4WT about 10 years ago with the supplied 'fixed' chassis, and it does look and run well, but I think I was lucky with the balancing etc. Similarly with a Craftsman Johnson 0-4-4T; there I had to fill the boiler with lead to balance it, although the end result is again pleasing.

 

I have been wondering about this idea of a sort of '2 bogie' arrangement; if nothing else, as was pointed out, it does help with the 'throw' of the rear on corners. Food for thought, as it were

 

Cheers

Mark

 

I posted these on the "future of kitbuilding" thread but as that has gone to 40 pages and many people will have lost the will to live, I am posting them again here.

 

They show the inderneath of Peter Denny's LD&ECR 0-4-4T loco, scratchbuilt around 40 odd years ago.

 

It is built with two bogies and can shunt six wheeled carriages (which also have a bit of overhang on curves) bunker first around curves of less than 3' radius.

 

I haven't had to take it to bits yet (and I won't unless it is necessary because I can't see how to dismantle it!) but the system works like a dream.

 

The coupled wheel bogie only turns by a small amount and the change is just about visible in the photos. The rear bogie is mounted on a fixed pivot.

 

Tony

[chaz]

Here's three photos of a compensated 0-6-0 chassis I'm working on for a friend... It's 9mm gauge/HOn30 and will have a 50:1 gearbox with a Mashima 1220 motor when it is complete. It's built up from laser cut brass and steel parts, steel turnings, etc...

 

I can build the same chassis down to 5.26mm gauge, using fine scale wheels, with a slightly narrower gearbox.

 

 

JeffB

 

Wow, that's most impressive Jeff.

 

Normally I would decry the use of flangeless drivers (unless the prototype had 'em - like the 9Fs) but with an ouside frame loco you can't really see the wheels anyway.

 

Chaz

[chaz]

I posted these on the "future of kitbuilding" thread but as that has gone to 40 pages and many people will have lost the will to live, I am posting them again here.

 

They show the inderneath of Peter Denny's LD&ECR 0-4-4T loco, scratchbuilt around 40 odd years ago.

 

It is built with two bogies and can shunt six wheeled carriages (which also have a bit of overhang on curves) bunker first around curves of less than 3' radius.

 

I haven't had to take it to bits yet (and I won't unless it is necessary because I can't see how to dismantle it!) but the system works like a dream.

 

The coupled wheel bogie only turns by a small amount and the change is just about visible in the photos. The rear bogie is mounted on a fixed pivot.

 

Tony

 

Thanks for posting Tony. If it was Peter Denny's loco I assume it's an EM model? Can we have a photo of it the right way up please?

[Sandy Harper]

To keep wheels clean I use M&M rolling road units that sit on the track. One of the units has sprung units under each wheel, rather than the bearings, and a piece of green pan scourer. The other wheels pick up normally and the wheel to be cleaned are 'scrubbed' clean.

 

For non driven wheels I use a steel or brass brush in the mini drill and hold it against the wheel tyre at the same time applying gentle pressure to the other wheel on the axle to slow it down. The difference in speed of the brush and the wheel takes the muck off.

Sandy

[JeffB]

Wow, that's most impressive Jeff.

 

Normally I would decry the use of flangeless drivers (unless the prototype had 'em - like the 9Fs) but with an ouside frame loco you can't really see the wheels anyway.

 

Chaz

 

Thanks Chaz... You see flangeless center drivers on a lot of 0-6-0's in the States. I have a similar chassis with a slightly longer wheelbase that used all flanged drivers, and could have done the same on the one in the photos, but I happened to have the flangeless ones built up, so I used them.

 

Jeff

[MarkC]

If you do Mark be sure to post an account of how it goes. I, for one, would be most interested to see how you get on.

 

Chaz

 

I certainly will, Chaz.

 

I'm just about to rejoin my ship for a 10 week tour of duty, so will hopefully get a chance to do some planning. No promises, of course...

 

Cheers

Mark

[MarkC]

I posted these on the "future of kitbuilding" thread but as that has gone to 40 pages and many people will have lost the will to live, I am posting them again here.

 

They show the inderneath of Peter Denny's LD&ECR 0-4-4T loco, scratchbuilt around 40 odd years ago.

 

It is built with two bogies and can shunt six wheeled carriages (which also have a bit of overhang on curves) bunker first around curves of less than 3' radius.

 

I haven't had to take it to bits yet (and I won't unless it is necessary because I can't see how to dismantle it!) but the system works like a dream.

 

The coupled wheel bogie only turns by a small amount and the change is just about visible in the photos. The rear bogie is mounted on a fixed pivot.

 

Tony

 

Cheers, Tony. Interesting.

 

Mark

[Miss Prism]

For those keen on or wedded to a fixed drive axle because of gearbox/motor considerations, the 'fixed axle and twin equalising beams' arrangement (see Chaz' posting) has a lot going for it, despite being 4-point compensation, and has the considerable advantage of being immune to the potential lateral instability of the 3-point arrangement:

 

 

If dimension X becomes small enough, the beams become springy, and any qualms about the 4-pointedness of the system disappear. In terms of implementing the height setting for these axles, the amount of thinking and planning required between the rigid and springy versions is about the same.

[chaz]

Hope you don't mind me referring to your sketch. The difference with full compensation would be that the axle you label as fixed would be free to rock - if you do this there is no instability - trust me I've done it. There is no tendency for the model to flop sideways, as we have true three point suspension. The main difference in performance between the two approaches is that with a fixed axle the whole loco must rock to respond changes in track level under the third axle, whereas with the three point arrangement the body will be less prone to movement. In my experience adhesion and electrical pickup are much the same with either method and if it is difficult to arrange a rocking third axle the scheme you illustrate serves very well.

 

My advice is not to go for "springy" beams. Any slackness in the control of axle height is likely to lead to a measure of instability. However it is an advantage if the metal that the beams are made of is not too thick. As the beams move up and down the axles will rock a little and there must be a little give to allow the wheel bearings to go with them. So I would keep dimension X generous enough to make the beam stiff in that plane but thin enough to allow the wheel bearings to rock. If they can't and they are a good running fit on the axles (which they should be to maintain the wheelbase) they will prevent the very movement we want to happen.

 

Remember, unless your track is appallingly bad, the vertical axle movements will be very small - fractions of a millimetre - but a rigid chassis which gives no movement at all will have these fractions of a millimetre between some of the wheel treads and the rail.

 

Sorry for going a bit - took me a while to get my head around compensation but once I "got it" its advantages over springing made it an easy choice.

 

However as always Rule One applies!

 

Chaz

[Miss Prism]

Chaz: I do not doubt for a moment the 'full compensation' arrangement you describe, i.e. twin beams between two axles plus a 'swing' central rocker on the third axle, works fine. All I was pointing out was that for those who feel bound (for whatever reason) to a fixed drive axle at one end of the chassis, twin beams over the other two will produce a more stable result than a single beam. (And from there, a degree of vertical flexure in the twin beams would be an added bonus.) The need for blocks to rock relative to the frame applies irrespective of which arrangement is used, and is merely a matter of appropriate beam shape and decent block and guide design.

 

I suspect our mutual target here is the single compensation beam method. I have seen many 3-axled locos with such working ok. I have also seen 3-axleds with exactly the same arrangement that do not work fine at all: they are laterally unstable. It really all depends on the placement of the CofG. In the general case, lateral stability and good weight distribution are incompatible in such an arrangement. A good case in point was Chris Gibbon's design saga for his High Level GWR 0-4-2T. Initially, he gave it the old-fashioned single beam arrangement of a fixed front axle and a central beam between the rear driver and the carrying axle. I told him it would fall over. He didn't believe me, and went ahead. The next time we met he said it hadn't worked out because it had indeed fallen over (on curves, of course). So he modified it to a 'full compensation' with a single rocker on the front driver and twin beams between the rear driver and the carrying axle, which is what we have in the production version. It works fine because of the specific CofG placement window arising from that specific loco.

 

Btw, given that a fixed axle confers complete lateral body stability, could you amplify your "Any slackness in the control of axle height is likely to lead to a measure of instability."

[t-b-g]

For another variation to throw into the melting pot, how about a fixed rear axle, a front axle which has a central pivot and a lightly sprung centre axle, just enough to hold the axle down on the track?

 

I have done it and it works a treat. No beams and the triangle of the three point suspension is spread as widely as possible over the wheelbase. On a six coupled loco with no carrying wheels, I can't see how it matters very much if the weight distribution is equal over all the wheels or if it is mostly on the front and back axles.

 

Tony