Help with 4-4-0T chassis, please - springs, compensation, CSBs?

[Daddyman]

Hello 

I'd like some views on what to do with a kitbuilt 00 4-4-0T chassis (specifically an ex-NBR class R/LNER D51). My plan is to build the front end with no secondary suspension, with the bogie axles rocking independently of each other on knife edges. This will mean I avoid the infamous problem of weight distribution in this wheel arrangement. However, weight distribution may not be a problem as the motor will sit roughly in the dead centre of the loco, and most of the space for the rear of the loco is at the rear.  

 

The question, then, is what to do about the drivers, given this bogie set-up. The layout on which this has to run until I get my own has some very slight baseboard warping. Running on the layout, my scratchbuilt D20, with no secondary suspension on the bogie and with the bogie wheels on a compensation beam, and with non-compensated driving wheels, has a slight problem on the warped section, where the track dips slightly, in that the front drivers just to say lose contact with the rail. My feeling is that some sort of springing or compensation would solve this issue on the D51. The layout also has one Peco point with the nasty void at the nose end (the rest being scratchbuilt): on short-wheelbase, small-wheeled locos this necessitates a rocking non-powered axle, though the D51 with a 29mm wheelbase and 5-foot-something drivers should be OK.  

 

So the options for the drivers seem to be: 

 

1. Use CSBs. Problem: can these be used on a loco with a bogie? Will my design at the front end cause problems with this system? 

 

2. Give the bogie secondary suspension and keep the drivers rigid. Problem: I have no idea how to spring a bogie, where to start looking for springs and how to get the springiness right. 

 

3. Use scratchbuilt compensation beams. Problem: what are the best hornblocks to use with such a set-up? I have limited clearance between the frames as this loco will be in 00. 

 

4. Spring the loco. Problem: I can't get Gibson's to work, Exactoscale have 5mm hornways rather than 6mm, and there's the limited clearance problem. Should I use the low-profile High Level hornblocks I bought for CSB but with individual springs, Bradwell-style? If so, how do I choose the wire thickness? 

 

I think there is an MRJ where (possibly) Iain Rice examines options for 0-4-4 and 4-4-0 chassis, but searching the index hasn't brought anything up; could anyone remind me of the number? 

 

Thanks in advance! 

[Miss Prism]

I think you need to separate your ideas/inclinations/desires on components to be used, particularly gearboxes, before you start to think about what suspension options might be available.

 

Your reading might include:

http://www.clag.org.uk/41-0rev.html

http://www.clag.org.uk/beam-annex3.html

http://www.clag.org.uk/class2p-bill.html

[Daddyman]

 

I think you need to separate your ideas/inclinations/desires on components to be used, particularly gearboxes, before you start to think about what suspension options might be available.

 

Your reading might include:

http://www.clag.org.uk/41-0rev.html

http://www.clag.org.uk/beam-annex3.html

http://www.clag.org.uk/class2p-bill.html

 

Gearbox is a HL RoadRunner + with 1424 Mashima and 45:1 gears. 

 

Thanks for the links. 

[DCB]

The  D51 must be the easiest 4-4-0 of all to balance. I thought you meant a D50 to begin with, now that was a beast!

A big solid slab of lead in the bunker and a D51 should run quite happily without a leading bogie.

If the D20 has issues with warped track I would fix the track.  I had the same issue with a T9. spent hours tweaking track back level especially cant wise side to side and sorting dips.  

My favoured ploy is to have a double chassis.  One which supports the leading bogie and rear axle and a second which supports both driving axles the motor and lots of ballast, one fits inside the other and they pivot around a driving axle, for appearance the motor on the inner chassis and the outer with oversize axle holes through which the bearing shoulders of the inner protrude. This limits the difference humps in the track make to haulage power. I have several part finished GWR 14XX with double chassis in my to do tin as we speak, stuck for decent split axle pick up 16mm wheels at present.

For the D51 I would make a very heavy bogie with limited sideplay and only about 1mm clearance before it lifts the front of the loco, its function being to stop the front buffer beam crabbing too far out of line, the bogie wheels hitting the frame and to take the coupling forces so probably best located on a single fixed pin. Add a light spring or two, Hornby Ringfield Brush Springs?  to taste

The biggest problem with 4-4-0 and 0-4-4 chassis after traction is keeping the buffers over the rails, huge numbers of otherwise worthy models wobble along like drunken ant eaters, not mentioning any RTR T9 in particular but with such a short loco limited sideplay on the bogie pivot and if necessary a few mill sideplay on the leading coupled axle should suffice.

Edited January 20, 2018 by DavidCBroad

[34theletterbetweenB&D]

I would tend to 'KISS' for OO.

 

There should be no problem balancing this machine as an 0-4-0 given the size of the side tanks and bunker. Will a rigid 0-4-0 run reliably on this layout would be the first question.

 

If so then let the bogie simply 'float' with a very light spring for trackholding, 10g pressure is enough.

 

If not, then give the leading coupled axle a spring ,and drive on the rear axle, put the bogie on a rigid pivot: equivalent to an 0-6-0 with centre axle sprung, very reliable.

[brossard]

You could use CSB components (those from High Level are excellent) for the undriven axle.  I suspect that for 00 your gearbox won't fit between even low profile hornblocks.  Another option to consider are the sprung hornblocks from Brassmasters and with these you may be able to spring both axles because they are close to be flush to the frames.

 

Iain Rice in his book on Etched Chassis Construction has ideas about springing and compensating bogies.

 

John

[Daddyman]

Thanks to all! 

 

I'm inclined to go with DavidCBroad or 34C's suggestions. A question, David: with a floating internal chassis, which I have on my 52F Models C15, isn't it a problem that unevenness in the track has to be even - that is, any dips must be equal on both sides of the track as there is no transverse rock with this set-up? This type of chassis does nothing to deal with the one-sided dip in the toe of a Peco turnout, if I understand correctly? 

 

Thanks, 

David. 

[benachie]

For 4-4-0s and 0-4-4s, I use a system introduced by Horton in the Railway Modeller of July 1964. It mimics the three-point suspension of coaches where, apart from rotation, one bogie is allowed to move in all directions but the other can only rock back and forth thus holding the vehicle vertical. In the case of a 4-4-0 (or 0-4-4) locomotive, the driving wheels are mounted in a rigid sub-chassis that is free to pivot fore and aft and the rest of the weight is transmitted to the track via a pillar onto the unconstrained bogie. Theoretically, because the 4-coupled unit is rigid, current collection via the drivers is not a good as with other systems but pickups on the bogie are possible.

 

Alan

[t-b-g]

I have built an 0-4-4t and a 4-4-0t both using a very simple and highly effective method. I carry the weight of the loco on the bogie pivot and, in the case of the 4-4-0, the rear driving axle, which just runs in plain bearings. The leading driving axle is given a small amount of up and down movement, just half a mm either side of centre. That axle can be lightly sprung to hold it down on the track for pick up purposes with a simple wire or strip spring. I don't use hornblocks and axleboxes, I just make a slot out of either thick material with a 1/8th slot, or I use two bits of brass angle soldered to the frames.

 

Any weight added behind the bogie pivot puts some on the driving wheel and a loco built like that has hauled 10 brass 4 wheeled carriages with ease.

[Daddyman]

For 4-4-0s and 0-4-4s, I use a system introduced by Horton in the Railway Modeller of July 1964. It mimics the three-point suspension of coaches where, apart from rotation, one bogie is allowed to move in all directions but the other can only rock back and forth thus holding the vehicle vertical. In the case of a 4-4-0 (or 0-4-4) locomotive, the driving wheels are mounted in a rigid sub-chassis that is free to pivot fore and aft and the rest of the weight is transmitted to the track via a pillar onto the unconstrained bogie. Theoretically, because the 4-coupled unit is rigid, current collection via the drivers is not a good as with other systems but pickups on the bogie are possible.

 

Alan

Thanks. This is DavidCBroad's suggestion, further up. 

 

 

I have built an 0-4-4t and a 4-4-0t both using a very simple and highly effective method. I carry the weight of the loco on the bogie pivot and, in the case of the 4-4-0, the rear driving axle, which just runs in plain bearings. The leading driving axle is given a small amount of up and down movement, just half a mm either side of centre. That axle can be lightly sprung to hold it down on the track for pick up purposes with a simple wire or strip spring. I don't use hornblocks and axleboxes, I just make a slot out of either thick material with a 1/8th slot, or I use two bits of brass angle soldered to the frames.

 

Any weight added behind the bogie pivot puts some on the driving wheel and a loco built like that has hauled 10 brass 4 wheeled carriages with ease.

Interesting. Is it the the driven axle that floats, though? I need to drive the front axle. 

[Miss Prism]

I need to drive the front axle.

Ha!

[t-b-g]

Thanks. This is DavidCBroad's suggestion, further up. 

 

 

 

Interesting. Is it the the driven axle that floats, though? I need to drive the front axle.

 

On the 4-4-0 I have the drive on the fixed axle. On the 0-4-4, the drive is on the rear, floating axle. The weight of the motor and gearbox helps keep it down on the track and I didn't bother with any springs on that one.

 

Apologies for the quality of the photos but the camera on this thing isn't great. You can see how I supported the bogie and transferred some weight to the front by extending the mounting arm.

[Miss Prism]

Nice flywheel!

[DCB]

Thanks to all! 

 

I'm inclined to go with DavidCBroad or 34C's suggestions. A question, David: with a floating internal chassis, which I have on my 52F Models C15, isn't it a problem that unevenness in the track has to be even - that is, any dips must be equal on both sides of the track as there is no transverse rock with this set-up? This type of chassis does nothing to deal with the one-sided dip in the toe of a Peco turnout, if I understand correctly? 

 

Thanks, 

David. 

The double chassis doesn't help the transverse unevenness issue but it stops the buffer beam waggling about, and evens out the traction over humps and dips.    I think a fully sprung non compensated chassis is needed for these asymmetric gaps but then you get issues with coupling rods which have to be sloppy so you end up driving both coupled axles to keep the coupling rods level (or not  see the 02). A three point suspension will still bang into the gaps on the rigid axle.   If the wheel standards are consistent one could shim the flangeways.  There is a recent post by someone recommending flangeway shims for Peco o gauge turnouts which might provide inspiration.   As for dips in plain track, get the PW gang out and level it up, Modern Image close the line for the weekend, Pre 1965 do it between trains.

[Daddyman]

The double chassis doesn't help the transverse unevenness issue but it stops the buffer beam waggling about, and evens out the traction over humps and dips.    I think a fully sprung non compensated chassis is needed for these asymmetric gaps but then you get issues with coupling rods which have to be sloppy so you end up driving both coupled axles to keep the coupling rods level (or not  see the 02). A three point suspension will still bang into the gaps on the rigid axle.   If the wheel standards are consistent one could shim the flangeways.  There is a recent post by someone recommending flangeway shims for Peco o gauge turnouts which might provide inspiration.   As for dips in plain track, get the PW gang out and level it up, Modern Image close the line for the weekend, Pre 1965 do it between trains.

Thanks again, David (and to t-b-g for the photos and clarification). 

 

The flangeways were shimmed right from the word go - there was no way we could do without. The baseboards were made 50 or 60 years ago, so we can't rip up the track and relay. 

[Jol Wilkinson]

I have just noticed this thread so this may be rather after the event.

 

The D51 has, as already pointed out, probably got space in the bunker and tanks for a good amount of ballast. The loco is quite short wheelbase and the bogie axles wouldn't need much vertical movement to accommodate the track irregularity.

 

 

For OO gauge I would therefore build the chassis rigid and spring the bogie axles. These would simply need the inside bearing holes enlarging up and down about .5mm and then fixing guitar wire "springs" to press down on the axles.

 

 

[Dave John]

Well, a similar 4-4-0. 

 

Fixed rear axle, beam from second driver to bogie. Split frame bogie for pickups, 3 point compensated bogie. Ok,  I'm not a painter, but it never stalls and handles 8 coaches with ease.

 

http://www.rmweb.co.uk/community/index.php?/blog/2091/entry-18429-some-maintenance/

[Daddyman]

Well, a similar 4-4-0. 

 

Fixed rear axle, beam from second driver to bogie. Split frame bogie for pickups, 3 point compensated bogie. Ok,  I'm not a painter, but it never stalls and handles 8 coaches with ease.

 

http://www.rmweb.co.uk/community/index.php?/blog/2091/entry-18429-some-maintenance/

Nowt wrong with that painting. You have actually built the compensation exactly as directed in the D51 kit. 

 

 

I have just noticed this thread so this may be rather after the event.

 

The D51 has, as already pointed out, probably got space in the bunker and tanks for a good amount of ballast. The loco is quite short wheelbase and the bogie axles wouldn't need much vertical movement to accommodate the track irregularity.

 

Drummond 440.jpg

 

For OO gauge I would therefore build the chassis rigid and spring the bogie axles. These would simply need the inside bearing holes enlarging up and down about .5mm and then fixing guitar wire "springs" to press down on the axles.

Thanks, Jol. The loco is, as you and others suggest, perfectly balanced without the bogie, both with and without the body on, so I've built it rigid for now and will face the springing and compensation demons when I convert to P4 in the future. Springing the bogie axles is not as easy as it should be, due to the channel shape of the bogie spacer, but yes, got there in the end. Now the problem is the width of the frames at the front - 13.5mm, which allows almost zero bogie swing. Still pondering that one. 

[ianmaccormac]

http://www.lbscrmodels.co.uk/index.html

 

Barry talks sense on his website about Plumpton, Pulborough etc. There is a good part about 4-4-0 chassis and some photos of solutions that have worked for years.

Cheers

Ian

[Jol Wilkinson]

Nowt wrong with that painting. You have actually built the compensation exactly as directed in the D51 kit. 

 

 

Thanks, Jol. The loco is, as you and others suggest, perfectly balanced without the bogie, both with and without the body on, so I've built it rigid for now and will face the springing and compensation demons when I convert to P4 in the future. Springing the bogie axles is not as easy as it should be, due to the channel shape of the bogie spacer, but yes, got there in the end. Now the problem is the width of the frames at the front - 13.5mm, which allows almost zero bogie swing. Still pondering that one. 

 

Have you built the bogie yet? If not you could drill some holes in the spacer for the spring wires to pass through. The attached shows the OO spacer from the LRM NER G1 4-4-0 front bogie to illustrate the idea.

 

OO spacer showing spring holes.pdf

 

The four sets of three holes are for fore and aft spring wires, the two pairs of holes are for wires to provide lateral centering springing against the bogie retaining bolt..

Edited January 25, 2018 by Jol Wilkinson

[benachie]

Thanks. This is DavidCBroad's suggestion, further up. 

 

 

I

Not quite since he seems to need a double chassis whereas I just suspend both the bogie and the 4-coupled chassis directly from the footplate.   Here is a "Director" so treated.   The footplate has a transverse wire that sits in the channel fixed to the 4-coupled chassis.   The bogie is suspended from the footplate by a screw which enables height adjustment.

Edited January 25, 2018 by benachie

[Daddyman]

Have you built the bogie yet? If not you could drill some holes in the spacer for the spring wires to pass through. The attached shows the OO spacer from the LRM NER G1 4-4-0 front bogie to illustrate the idea.

 

OO spacer showing spring holes.pdf

 

The four sets of three holes are for fore and aft spring wires, the two pairs of holes are for wires to provide lateral centering springing against the bogie retaining bolt..

Thanks, Jol, very useful. I've sawn slots instead, as I'd already made up the main bogie body. 

Edited January 25, 2018 by Daddyman

[ian@stenochs]

I have built an 0-4-4t and a 4-4-0t both using a very simple and highly effective method. I carry the weight of the loco on the bogie pivot and, in the case of the 4-4-0, the rear driving axle, which just runs in plain bearings. The leading driving axle is given a small amount of up and down movement, just half a mm either side of centre. That axle can be lightly sprung to hold it down on the track for pick up purposes with a simple wire or strip spring. I don't use hornblocks and axleboxes, I just make a slot out of either thick material with a 1/8th slot, or I use two bits of brass angle soldered to the frames.

Any weight added behind the bogie pivot puts some on the driving wheel and a loco built like that has hauled 10 brass 4 wheeled carriages with ease.

I use the same system in S7 for 0-4-4Ts. However to minimise rear buffer throw I support the loco rear end on the bogie centre but pivot the bogie just in front of the inner axle. The bogie is three point suspended with the rigid axle at the front and the other axle pivoted at its midpoint. Because the sprung driven axle is within the tanks plenty of sideplay can be given to the wheels without compromising looks.

 

I haven’t used the system on 4-4-0s because the inside motion tends to get in the way!

 

Ian.