New Bachmann Class 24 P4 conversion

[David Thorpe]

Hello everyone, I'm back - the Society has kindly agreed to re-admit me after a couple of years absence. Recently I decided on a modernisation programme for my layout and am acquiring some diesels. The first is the new sound-equipped Bachmann Class 24, not to be confused with the earlier Bachmann model, one of which I converted some years ago. Relying on Keith Norgrove's excellent instructions conversion of that model was not difficult and so I assumed that the new one using the Gibson replacement wheelsets would be much the same.

It isn't.

First I had difficulty removing the body. Relying on the information sheet that came with the model I duly unscrewed what I thought were the necessary six screws, after which the body refused to come off. A quick search of RMWeb showed that, in common with lots of other people, I'd undone the wrong screws. So I did them up again, found the right screws (hidden by the bogies) and the body duly came off. Why remove the body at all to do a wheel conversion? Keith had rightly advised that removal of the bodyshell and release of the bogies from the chassis would make it easier to unclip the bogie frames. To do that you'd remove two pivot screws, easily accessible on the old class 24. But not on the new one. If the bogie pivot screws are to be accessed, it seems that I'm first going to have to remove the printed circuit board (much longer than in the previous model) and I'm reluctant to do that as some of the wires attached to it are short and I fear might well come away with my rather clumsy handling (things don't get easier as you get older), and even then there's no guarantee that I'll be able to get at the bogie pivot screws. And even if I do get the bogies off, examination of them still on the body gives no indication as to how the bogie frame can be unclipped. There are a couple of screws in the bottom of the bogie keeper plate, but removal of them doesn't seem to achieve anything.

I wonder if anyone has tackled this? If so, I'd be very grateful for any advice as to how to go about it.

[Daddyman]

There's no need to undo the bogie pivot screws! I take new Bachmann 37 bogie frames off all the time and it's never occurred to me to undo the pivot screws. On the 37, there are two screws on the base of the bogie, which seem to be the same as on your 24; undo these and the bogies should unclip - they have the same clips at either end that the old pre-bogie-baseplate screw models had, though the new clips seem less "aggressive". I'm surprised the frames haven't fallen off once you undid the screws as they do on the 37. You should certainly only need some gentle levering at one end or another.

[David Thorpe]

Thankyou for getting bck to me. However, I'm still stuck. I duly removed the two screws and assumed that situated where they were they would release the base of the bogie. However, nothing moved even slightly. I have poked and prodded at what I thought were fairly likely points but to no avail, though I have managed to remove the coupling. I had thought that there might be a clip at each end of the bogie, but if there are they are impervious to my efforts to undo them. I'm attaching a photo of the bogie and wonder if it is iundeed the same as your class 37 and if so, what you did to get into the thing once you'd removed the screws (which have been removed in the photo). A trace of my efforts to get into what I think might be a clip at the rright hand side can be seen!:

class24.jpg

[Daddyman]

This post from Porcy Mane on RMWeb confirms my suspicions that it's the same as the 37: "For some reason Bachmann have chosen to fix the metal bogie centres to the outer plastic frame with two additional self tappers in addition to the two end clips as used on the earlier type bogies. I've no idea why".
Personally, I welcome this new system as it means the clips aren't doing so much work, which means the bogies no longer disintegrate as the old ones did with the force needed to undo the clips. However, I notice that you mention a baseplate, and that might be where you're going wrong: there is no baseplate on these bogies; they are one complete unit with outer frames, ends and base, and I wonder if you might be levering it the wrong way expecting the baseplate to detach from the frames. You also seem from the photo to be levering at it the wrong way: remember the bogie frame needs to move downwards so you'd be better levering at the rear of the bogies frame from above. But I'm surprised they don't just come away of their own accord, or with a little finger pressure - I've just watched myself do it and I have my thumb on the base of the bogie and ease a rear corner (either one) sort of diagonally downwards with my forefinger.

I'm surprised Porcy hasn't been along with one of his new-fangled daguerreotypes.

[David Thorpe]

Again, thanks for your help - I shall hopefully get time this afternoon to have another shot at these bogies. Meanwhile, because I was still having difficulty even after your advice I sent an email to Bachmann yesterday evening asking how to release the wheels and I was both surprised and impressed to receive a very speedy response. It was:

"Once the two screws securing the bogie frame to the bogie inner have been removed there are a couple of clips that also need releasing to remove the bogie frame. The clips are located at the front and rear of the bogie inner and can be released by gently levering the frame away from the inner. By using a pair of tweezers or similar, it is possible to lever the frame away by using the wheels as a point to lever against with the nose of the tweezers underneath the frame. Once the clips have been released the frame should lift off easily."

From that it seems that the 24 bogies may be a lttle different from the 37 ones in that there are clips involved, possibly quite strong clips if my experience is anything to go by. Anyway, I'll try your finger and thumb method first and if that doesn't work I'll get the tweezers out and see if I can lever the frame away although I'm not quite sure what is meant by the "bogie inner" - all being well it will be obvious. However I hope it doesn't come to that as all too often in my experience using a metal lever on plastic leads to broken plastic. Here's hoping.

In my new quest for dieselisation I've also got an Accurascale class 37 on pre-order, and I've already bought the Accurascale "drop in" P4 wheels for it. Having read various comments online it seems that that conversion also may not be without problems. We shall see....
.

[Daddyman]

From that it seems that the 24 bogies may be a lttle different from the 37 ones in that there are clips involved, possibly quite strong clips if my experience is anything to go by. Anyway, I'll try your finger and thumb method first and if that doesn't work I'll get the tweezers out and see if I can lever the frame away although I'm not quite sure what is meant by the "bogie inner" - all being well it will be obvious. However I hope it doesn't come to that as all too often in my experience using a metal lever on plastic leads to broken plastic. Here's hoping.

By "bogie inner" they mean the frame in which the wheels and gears are held, onto which the bogie frame screws and clips. This is exactly the same as the 37. And the same as the old class 24, which you seem to have had at one point - you're essentially levering at the same points you did on the old model, but with less force.

On the 37 at least there is much less leverage involved, which, if the 24 is the same, should reduce the likelihood of broken plastic.
I've had 16 bogies apart on the 37, and haven't broken one, whereas on the old model I broke ever single one.

an Accurascale class 37

Sorry, I have nothing helpful or polite to offer there.

This may help, I don't know:

20240115_130034.jpg

[Porcy Mane]

I'm surprised Porcy hasn't been along with one of his new-fangled daguerreotypes.

Hello David,

I've just had a phone call alerting me to this post. I've converted a few late Bachmann 24's to P4 (And EM) as has Rick. Short of time at the moment but I'll try and make time to do a more in depth reply tonight.

The late 24 doesn't use screws for bogie retention but a combined worm keep cum retaining clip in the same manner as the SLW 24/5. It gives a much lower pivot point, a single spigot, to give pitch roll & yaw to the bogie.

In the meantime a pic of Bachmann/SLW compared. Ringed in red are the B'mann bogie components.

B'mann-2020-24-021-EditSmII.jpg

[Porcy Mane]

There may be better ways of converting the latest Bachmann class 24 to P4 but here are a couple of methods I’ve used.

Bogie Removal

As the original poster has mentioned, like the original B’mann, 24, the bogie moulding is designed to be removed by levering the bogie ends from the top (cab) side but with the extra step of removing the two additional screws.

With David and my pal, they’ve found it easy to lever the combined bogie outer frame/keeper plate without dropping the bogies out of the main chassis to swap the wheels. As I was doing a complete strip down with mine as I wanted to fit resonator boxes for a twin DCC speaker set up and do something to limit the free motor rotation before drive was taken up; so I never got round to just trying to remove the bogie frame whilst leaving the rest of the assembly attached.

I found with the body removed it only took about fifteen minutes to disconnect the JST connectors, remove the moulded cab interiors (one screw apiece accessed from the outside, behind the buffer beam) followed by the main PCB (five screws) complete with its two auxiliary cab PCB’s (two screws apiece). With the PCB’s out of the way there’s plenty of access to the bogie top with its retaining clip. Removing the clip, arrowed in the phot, allows the bogies to fall away complete with its associated wiring and JST connector.

B'mann-2020-24-040-EditSm.jpg

Bachmann class 24 chassis PCB's

B'mann-2020-24-036-EditSmS4m.jpg

SLW chassis to top, B'mann at bottom.

With the bogie moulding removed from its metal inner, the plastic brake linkages which are affixed to the inside have to be thinned to allow P4 wheelsets to be fitted.

I don’t know why Bachmann has gone for the belt & braces technique of both screws & clips to retain the bogie moulding but as I run my locos on both P4 & EM layouts, I’ll be filing the retaining “wedge” off the inner end of the bogie and just relying on the two screws for fixing. This should make wheel swaps a lot easier and less time consuming in future.


Wheels, axles etc.

Ultrascale.

Unless Ultrascale have updated their Bachmann Class 24 P4 wheel-sets from the early version, fitting them to the 2020 Class 24’s requires the brass final drive pinion to be replaced on the axle with the B’mann nylon pinion. The final drive pinion on the updated 24 is a smaller diameter and uses helical gears as opposed to straight cut gears on the original. Also the bosses on the inside face of the Ultrascale wheel have to be reduced in width to achieve the 17.75mm back to back as the original plastic inner “chassis” with clip in brass bearings is narrower than the current metal inner with “horn block” type bearings.

Ultrascale also do an economy 24 conversion that is supplied without the final drive pinion but there is the uncertainty of supply at the moment and long lead time for delivery. Unless you have Ultrascales in stock I’d discount them.

SLW class 24 P4 wheel-sets.
https://railexclusive.com/product/class-24-em-p4-wheelsets-installed/

Cheap at £20.00 for a loco, in stock with very quick delivery. (I ordered another set yesterday afternoon).
The final drive pinion and squared bearings still needs salvaging from the B’mann wheel/axle to replace the SLW bearings & pinion but it was a job I managed without resorting to my pullers and wheel press. I found the bosses on the rear of the SLW wheels the perfect length giving just the right amount of side play.

Alternately if you want to keep the original axles complete, B’mann spares will sell you a single wheel-set compete with bearings and pinion for a fiver. Part No. E3244-272-1https://bachmann-spares.co.uk/product/category/710/class-24-2020-geared-axles-32-440/e3244-272-01. Make sure you get the current version of wheel-sets not the original Mk.1 version.

B'mann-2020-24-159-©PwD2024-EditSm.jpg

Above pic shows a bogie with B;mann standard 24 wheels pulled out to EM gauge. The left wheels are Ultrascale 24 wheelsets with B'mann final drive pinion and square bearings fitted, R.H. wheelsets are SLW P4's as supplied.

B'mann-2020-24-162-©PwD-2024-EditSm.jpg

B'mann std. wheelset to left, Ultrascale P4 in centre & SLW P4 at right.

The methods outlined above should be good for carrying out a P4 conversion for the latest Bachmann 37 but using Accurascale 37 P4 wheels as opposed to the SLW wheelsets.

Hope that helps and it hasn't left folk as confused as I've just become.

P

[Daddyman]

I’ll be filing the retaining “wedge” off the inner end of the bogie and just relying on the two screws for fixing.

Good idea, that. Thanks Porcy!

[Porcy Mane]

I’ll be filing the retaining “wedge” off the inner end of the bogie and just relying on the two screws for fixing.

Good idea, that. Thanks Porcy!

I'm sure some one else will have come up with that idea previously.

Just to show that it all goes back together. Twin speakers installed and just leaving enough room to fit a rotating cooler group fan.

B'mann-2020-24-146-© PwD 2024-EditSm.jpg

P

[David Thorpe]

Unfortunately I haven't yet had an opportunity to do any further work on my Class 24, but hopefully will do so tomorrow - I'll report back further then. I'm very grateful to everyone on this thread for their contributions.

[Daddyman]

Unfortunately I haven't yet had an opportunity to do any further work on my Class 24, but hopefully will do so tomorrow - I'll report back further then. I'm very grateful to everyone on this thread for their contributions.

If you're still stuck, David, we could try to do something on Zoom (or Teams) if you're familiar with either.

Remember also that you could try using a piece of plasticard as a lever, if you're worried about using a metal lever. But I really do think that once you start levering in the right direction, finger pressure will be enough.

[David Thorpe]

Thank you David, I may well take you up on your Zoom offer if I can't manage this myself.

The trouble is that I'm frightened of breaking anything. I'm attaching a photo of one of the bogies - am I right in thinking that thr gap with a blue arrow pointing to it is where you'd endeavour to insert an implement (screwdriver, tweezers, whatever) in an attempt to separate the two parts? I have in fact already made an attempt along these lines - you'll see a small glint of metal where I tried inserting a screwdriver - but the screwdriver blade wouldn't go in at all and I didn't want to push too hard!

Paul, your diagrams are very useful. I'd like to avoid dis=assembling the model if possible but if I can't lever the bogies apart while they're still attached even after getting help from David I'll proceed in accordance with your diagram. I'll be using Gibson replacement wheels.

class24 arrow.png

[Porcy Mane]

The trouble is that I'm frightened of breaking anything.

I think it would be better if you rotate the bogie to it's maximum then try levering off the bogie frame by its inner wedge. As in David's photograph above.

B'mann-2020-24-157-©PwD-EditSm.jpg

Should you damage the bogie moulding Bachmann can supply spare mouldings complete with fixture & fittings for what I think is a very reasonable £5.00 + p&p.

https://bachmann-spares.co.uk/category/ ... s25?page=4

The Bachmann spares page takes a while to load up the images.

P

[Daddyman]

am I right in thinking that thr gap with a blue arrow pointing to it is where you'd endeavour to insert an implement (screwdriver, tweezers, whatever)

No, David - that won't do any good: the clips on the end of the metal part (the inner bogie) slope upwards, which means you have to prise the plastic bogie frame out from above, as it needs to be made to splay out to clear the metal clips, to allow the bogie frame to go downwards (i.e., as Paul says, trackwards). Pushing where it looks like you have been won't achieve anything as you seem to be pushing against the base of the bogie, which has nowhere to go, and if you're pushing against the clip itself, hoping it will bend inwards as clips on some models do, it won't work as you're trying to flex a very inflexible Mazak clip. To put it another way, the part of the plastic bogie that needs to flex to clear the clips on the metal inner frame is the upper part of the bogie rear - the member that crosses between sides; in other words, insert something (plastic maybe) from the top of the bogie: swing the bogie fully over to the same side (as in my photo) that you are trying to flex and lever any part of the uppermost part of the bogie rear that you can get to. Paul's red arrow is in the right place, but it doesn't quite make clear that you need to approach from the top of the bogie.

Paul makes a good point about Bachmann spares, but hopefully it won't come to that.

Some pics:

You seem to be pushing at the point of my arrow "bogie rear (section thru at centre)" - albeit at the front of the bogie; hopefully you can see that does no good.

20240117_074924.jpg

Because the tabs/clips on the new bogies are not as pronounced as on the old ones, most of your leverage can be trackwards, with only a slight hint of rearwards:

20240117_074334.jpg

In this photo you can just about see the tab/clip on the rear of the bogie that you're trying to clear:

20240117_074446.jpg

[Will L]

20240117_074924.jpg

As somebody who has been watching this discussion with amused disinterest (nothing like that ever ran on my railway) and trying to work out exactly what the written descriptions implied, realisation dawned with this picture. Seems to prove the point about words and pictures.

[Daddyman]

pictures

Maybe those books I've been reading on nineteenth-century art are paying off...

Let's hope it's clear to David too!

[David Thorpe]

I'm just back in after stacking away a load of logs delivered this morning. It's a very cold day, an inch and a half of snow, but bright sun in a cloudless blue sky, and my fingers are frozen and I'm "nackered. Maybe after a cup of tea and a long feet-up in front of a fire made by some of these logs I'll feel capable of turning to my Class 24! But yes, David's hand-drawn picture has indeed made things clearer and confirmed that I've been going about things in entirely the wrong way.

[David Thorpe]

I've had another go, again unsuccessfully, but having looked again at the pictures you have kindly provided I'm beginning to think that,quite apart from the difference in wheel arrangement, the bogies on your 37 are not the same as those in my 24 - there's no way, for example, that I could get a blade where you've inserted one in your recent set of pictures (or at least, I've tried and I don't think I can). My 24 is a 24/0, 32-415SF - I'll try to take a close up picture of the bogie in daylight tomorrow.

[Daddyman]

I've had another go, again unsuccessfully, but having looked again at the pictures you have kindly provided I'm beginning to think that,quite apart from the difference in wheel arrangement, the bogies on your 37 are not the same as those in my 24 - there's no way, for example, that I could get a blade where you've inserted one in your recent set of pictures (or at least, I've tried and I don't think I can). My 24 is a 24/0, 32-415SF - I'll try to take a close up picture of the bogie in daylight tomorrow.

The blade's not actually doing anything - just for show really. Fingers should do it. There really is no difference in the bogies, as Paul's last picture shows.

[David Thorpe]

OK< to avoid any misunderstanding - finger and thumb. With the loco upside down resting on its roof, the thumb rests on the plasic base of the bogie, ie on the bottom of the bogie frame, and the (index) finger at a corner of the bogie pulls upwards (ie away from the loco body) following which the plastic frame should come away and part company with the metal bogie, the latter remining in place. Initially I misundersood and tried to push the frame downwrds with my finger, ie towards the loco body, which of course had no effect, but I've now spent some time trying to pull the corner of the frame upwards (ie towards me, away from the loco body), and while the corner of the frame bent up and some thin bits of plastic have broken, it has remained stubbornly in place and I've been left with a sore finger (it still hurts as I type this). I've tried this on both bogies, sevaral corners.

I'm beginning to despair somewhat. While I can't remember the details I had no real trouble converting the old class 24 and I don't understand why I'm having such problems with this one, especially as it's supposed to be easier! I think I'll go and nurse my finger, pour myself a dram, regain my composure, and try again in the morning!

[David Thorpe]

Belay that last posting - I've got them off! Fortified by the aforesaid dram I followed the Bachmann instruction and levered the frame away with a screwdriver poked through the gap between the wheels and the end of the frame and using a wheel as a fulcrum. Some more bits of plastic exhibited signs of distress, but once I'd found out how to get the first bogie off I had no real problem with the second. Looking back on it, I think that with the finger I'd been concentrating on pulling the frame upwards, while the screwdriver did what David's sketch showed and pulled it both upwards and outwards, thereby releasing the clip. I can't face putting them back on with those wretched clips in place so I think I'll follow Paul's suggestion and file one of the wedges off. Finger's still sore though!

My troubles may not yet be over, however - as Paul said earlier, some plastic has to be taken off the inside of the Bachmann frames in order to accommodate the P4 wheels. The frames already look very thin so I will require to proceed with caution.

Thanks to you both, David and Paul, for your help in this. I don't know what I would have done without it.

[Daddyman]

Well done, David! I was running out of suggestions! Lying awake at 4am worrying about it, all I could think of was tapping it - or failing that, dropping it. It might be helpful to others in a similar situation to know what the dram was that finally got it off. Do file the tabs off yes. I'll be filing mine off in solidarity.

Re thinning down plastic, I don't think it's the frame that needs thinning, is it?, but the brake rigging. I couldn't see a way of doing that on the 37 so drilled into the linkage where it meets the brake shoes, in line with/on the line of the brake pull rods, then replaced the latter with 0.4 wire, running through the hole drilled in the brake shoe, and superglued to the inside of the bogie frame. A picture for Will! - actually, make that three as they all have flaws as photos

20230729_144415.jpg

20230729_144751.jpg

Excuse the arrows - they were to show someone where I fit my replacement handbrake chains.

20230729_144803.jpg

However, I notice that the 24s seem to have brake rigging top and bottom (or is one a sander linkage?), and that the top rod is square section, which might cause a problem. You could use flattened wire, but I'm not sure where you'd anchor it - drilling through the brake shoes gave me a very strong anchor.

[David Thorpe]

Thanks David, I'm quite touched that you should lie awake at night thinking about my problems! I shall now proceed slowly with this project and may even put it aside until next week when I'm due to meet up with a friend who is both an excellent modeller and keen on diesels. (Heretical statement now coming up): If in fitting the wheels I lose a few bits from the bogies that I consider insignificant I won't be unduly concerned as by the time I've weathered everything and it's on the layout finest detail is unlikely to be visible and if it isn't visible (or, dare I see it, even if it's just that no-one will notice if it's not there) I won't be too concerned!

[Porcy Mane]

However, I notice that the 24s seem to have brake rigging top and bottom (or is one a sander linkage?)

BogieTests12-Crewe-M&amp;Edept-LMRpro.jpg

Probably muddies the water but might be some help. It's a bogie from D5061 undergoing testing at Crewe in 1960. The photograph is one a a large series, commissioned by the Mech. & Elec. Engineers Dept. and distributed to the railway press of the day by the Public Relations Office for LM Region.

P