Converting Hornby's EMU motor bogie to P4

[HAB]

Hornby's 2 BIL EMU could easily be justified for my current layout, so having obtained one (plus a few spare motor bogies) I set about devising a method of converting it to my chosen P4 (18.83mm) gauge.  These notes might be of interest as a source of ideas for other motor bogies and also for EM modellers contemplating such conversions.

 

My first method utilised Ultrascale wheels.  These are an excellent product - very well made, accurate and as tough as old boots.  They achieve that toughness by means of an extended boss on the back of the wheel centre.  Conversion was simply a matter of disassembling the bogie into its components, punching the Hornby wheels off the axles (which requires some fair brutality),  The Ultrascale wheel are then pushed onto the Hornby axles and, by virtue of their extended bosses, they can be happily set to gauge despite the axles being somewhat sort of length.  Once the pickups have been bent out to meet the wheels, the skeleton bogie will be a runner.  However, before the bogie can be re-assembled, there is the inevitable need to file material off the inside of the sideframes - a messy job and also one needing care to avoid damage to the brake pull rods.

 

 

You can see that the bosses on the wheels snugly fit against the sides of the gearbox - thus eliminating the sideplay which makes these bogies a bit of a nightmare in 00.  However, this might mean that this approach would not do for those working in EM or for 00 modellers just looking for better wheels.  But is is simple enough, and it works fine and is running about to this day. But two aspects of this approach bothered me.  Firstly, pushing Ultrascale wheels onto the splined Hornby axle smacks a bit of ill-treatment of a very nice product. Secondly, because the Ultrascale wheels are the "standard" (ie slightly overscale) width of 2mm in the tyre, there is a fair amount of material to be filed off the insides of the sideframes. 

 

So I set out to find a method of using the very nice Eactoscale wheels - which have scale width tyres.  this method has the potential to suit any make of motor bogie which uses 2mm diameter axles,

 

The Exactoscale wheels ( http://www.finescale.org.uk/index.php?route=product/category&path=541_542_545_546_547 ) differ from other makes in that they are assembled using Loctite 603 onto a 1mm dia axle which incorporates a moulded plastic representation of the prototype axle. (it is very important to follow the instructions, but if you do so, the result is a very accurate wheelset which will stay to gauge) But it struck me that any 1mm diameter hard-steel could be used as an axle, and that by using 1mm bore, 2mm OD tube, a 2mm diameter axle could also be achieved.

 

Looking through the Eileen's Emporium Lists (https://www.eileensemporium.co.uk/index.php?option=com_virtuemart&page=shop.browse&category_id=332&Itemid=9 ) i saw that they do 1mm ID x 2m OD tube in stainless steel along with 1mm piano wire - this is just what we need.  So the first stage is to cut a length of piano wire (it is hard - use a slitting disc!) to the overall length of the axle, and cut a piece of stainless steel tube long enough to fit between the bosses on the wheels and to suit the back-to-back.

 

 

 

The next step is to fit the Hornby gears etc to the tube and to assemble the wheels sets:-

 

 

 

The tubes and wheelsets are secured to the piano wire axles using Loctite 603 as described in the Exactoscale instuctions.

Now the wheelsets can be refitted to the motor / gearbox and the pickups bent to suit

 

 

All that is left to do now is to file back the inside of the frames - much less of this is needed as the tyres are scale width - and put the thing back together:-

 

 

All in all that is a pretty easy job and takes no more than an evening.

 

Hope that helps for those contemplating a similar project (and also to dispel the myth that bodging has no place in P4 modelling!!!)

 

Now, what about my 9F...

 

Best wishes,

 

Edited to get rid of all the white space!

[Colin parks]

Hi Howard,

 

That looks like a very elegant solution using Exatoscale wheels.  Now I am adopting the P4 for dummies approach, which will include bodging wherever possible, so what about using  Ultrascale wheels and widening the motor bogie's sides frames by the requisite amount? The plastic used for the Hornby 2 BIL is compatible with Liquid Poly, so a suitable solvent exists for the job.

 

 

I shall have to measure the Hornby bogie to see if what I suggest throws the  shoe beam out of alignment with the third rail, and get back to you.

 

All the best,

 

Colin

[HAB]

Hi Colin. 

 

In truth filing off the insides of the frames is not a big deal and would probably be much easier than a cut and shut on the frame as that would potentially interfere with the clip fit on the motor/gearbox. 

 

Bodge or not, the Ultrascale solution works fine - but I am hoping to convert you to engineered solutions :-)

 

Very Best Wishes,

[Colin parks]

Hi Howard,

 

Me again. What did you do regarding the other bogies on the 2 BIL? Are the other wheels of your preferred Ultrascale brand and are they running directly in the plastic bogie side frames or have you fitted brass bearings?

 

All the best,

 

Colin

[HAB]

Hi Colin.

 

The trailers were simply a case of removing the brake blocks (which no one has yet noticed - keep it quiet) and replacing the wheels - Ultrascale or Exactoscale both fit.  The only issue is the (incorrect) shoe beam bogie which requires the inside of the frames hacking about as per the Motor.

 

I confess that I don't bother fitting brass bearing cups - even though I do add a fair bit of extra weight by adding lead under the seats. I might well have a different approach were my layout another "Retford" - but it is not.  I suppose in several years time I might notice some wear here - that is when I will fit some brass cups!

 

Not my place to give advice, but if I were you I would be tempted to go for a "quick and easy" conversion of the BIL as a first off (after the wheel-swap class 73) to get some experience of what P4 is all about - if you don't like how it runs you can always back-track later, but I think you might be very pleasantly surprised.

 

Just as an aside, Bachmann trailer bogies are quite a bit more challenging because of the split frame current collection.  The S4 Society do some replacement stretchers to widen the frames, but the metal bogie inserts need splitting to avoid a short. All in all, that is a less satisfactory job - well alright, bodge. Having said that, I have had no issues with my EPB.

 

Hope that helps!

 

Very Best Wishes,

[Nimbus]

So I set out to find a method of using the very nice Exactoscale wheels - which have scale width tyres.  this method has the potential to suit any make of motor bogie which uses 2mm diameter axles,

 

The Exactoscale wheels ( http://www.finescale.org.uk/index.php?route=product/category&path=541_542_545_546_547 ) differ from other makes in that they are assembled using Loctite 603 onto a 1mm dia axle which incorporates a moulded plastic representation of the prototype axle. (it is very important to follow the instructions, but if you do so, the result is a very accurate wheelset which will stay to gauge) But it struck me that any 1mm diameter hard-steel could be used as an axle, and that by using 1mm bore, 2mm OD tube, a 2mm diameter axle could also be achieved.

 

Looking through the Eileen's Emporium Lists (https://www.eileensemporium.co.uk/index.php?option=com_virtuemart&page=shop.browse&category_id=332&Itemid=9 ) i saw that they do 1mm ID x 2m OD tube in stainless steel along with 1mm piano wire - this is just what we need.  So the first stage is to cut a length of piano wire (it is hard - use a slitting disc!) to the overall length of the axle, and cut a piece of stainless steel tube long enough to fit between the bosses on the wheels and to suit the back-to-back.

 

Part assembled.jpg

 

I have been wondering whether to use these wheels for locomotives, since I suspect we'll be a long time waiting for a purpose-engineered solution from Exactoscale. Prototype wheel-to-sideframe clearances are around 1" per side on a Class 20, so the scale width tyre is almost a must!

 

My one concern is that the centre metal bush may not be keyed to the plastic wheel dish such that it will indefinitely transmit traction torque. The first batch of Exactoscale wagon wheels were certainly not secure on their bushes (they clicked in the axial direction), but the manufacturing process or design was amended to stop this.

 

It's probably never going to become an issue with distributed traction on a MU train, though.

 

The Nim.

[HAB]

Hi Nim,

 

The current wheels are very different from the early ones - not only are the tyres stainless steel, but they are very strong.  I had the bad luck to put a set together out of gauge - I certainly could not budge it.  Eventually, I did get the centre to turn a bit on the bush, but it was still VERY tight.

 

I think you would have no worries at all.

 

Cheers,

[Colin parks]

Hi Colin.

 

The trailers were simply a case of removing the brake blocks (which no one has yet noticed - keep it quiet) and replacing the wheels - Ultrascale or Exactoscale both fit.  The only issue is the (incorrect) shoe beam bogie which requires the inside of the frames hacking about as per the Motor.

 

I confess that I don't bother fitting brass bearing cups - even though I do add a fair bit of extra weight by adding lead under the seats. I might well have a different approach were my layout another "Retford" - but it is not.  I suppose in several years time I might notice some wear here - that is when I will fit some brass cups!

 

Not my place to give advice, but if I were you I would be tempted to go for a "quick and easy" conversion of the BIL as a first off (after the wheel-swap class 73) to get some experience of what P4 is all about - if you don't like how it runs you can always back-track later, but I think you might be very pleasantly surprised.

 

Just as an aside, Bachmann trailer bogies are quite a bit more challenging because of the split frame current collection.  The S4 Society do some replacement stretchers to widen the frames, but the metal bogie inserts need splitting to avoid a short. All in all, that is a less satisfactory job - well alright, bodge. Having said that, I have had no issues with my EPB.

 

Hope that helps!

 

Very Best Wishes,

[/quo

Hi Howard,

 

Removing the brake blocks? I hadn't thought of that! As the 2 BIL of mine has not had bearings fitted to the trailing bogies, so I'll just adopt your approach and see what happens (when I get around to converting it).

 

Re. the motor bogie side frames: why did Hornby make them so narrow. Having checked my 2 BIL yesterday the difference in width between the 8ft w.b. bogie frames and those of the motor bogie is about 2mm. It still looks feasible to me to cut the side frames and pack each point of attachment to the central part of the moulding with 20 thou. styrene (black being the ideal colour). (Those cranked guard irons have to go too!) Having examined the side frame moulding- all the clips would remain undisturbed by this work and it would solve all the clearance problems.

 

I shall report back on how this goes at a much later date - I have no P4 wheels yet anyway!

 

All the best,

 

Colin

[HAB]

Hi Colin,

 

Hard to know why the frames are a bit narrow, but it might be to allow the shoes fuses to be mounted on the solebar rather than on the bogie frame - which is Bachmann's compromise.  So you might want to just do a check on that aspect. 

 

For "those of us who model in P4" (you will get used to it,,,) the fit of shoe the beams over the juice rail is not too bad (you will recall the pic I posted before in your SUB thread) so that also might be a factor.

 

Very Best Wishes,

 

 

 

 

[Colin parks]

Hi Colin,

 

Hard to know why the frames are a bit narrow, but it might be to allow the shoes fuses to be mounted on the solebar rather than on the bogie frame - which is Bachmann's compromise.  So you might want to just do a check on that aspect. 

 

For "those of us who model in P4" (you will get used to it,,,) the fit of shoe the beams over the juice rail is not too bad (you will recall the pic I posted before in your SUB thread) so that also might be a factor.

 

Very Best Wishes,

Hi Howard,

 

I hadn't considered the matter of the shoe fuses being the reason for the narrowness of the motor bogie frames. Mind you, everything is negotiable and I never did like the look of Hornby's shoe fuses anyway! As for the shoe beams, once the pick-up shoes have be relocated to be in line with the inner face of the beam, widening the bogie frames might just bring everything back into alignment. It is just a case of filing the axle boxes down a little if the beams are too wide.

 

Hey, lets just stick to 00 - only joking!

 

Colin

[HAB]

.. Hmm, you had me in a sweat for a second with the last comment...

 

I seem to recall you saying you were happy with your BIL - sounds now like you are ready to think again!!  New shoe fuses, that will show up the equipment fuses...... where next???

 

But I have to say that - speaking generally - "modern" RTR stock does increasingly seem to be made with wider gauges in mind - as an example, I have a Hornby "Schools" half done, and in the case of the tender, the frames were quite wide enough to allow a wheel swap. And my Heljan BRCW / Crompton Type 3 took all of half an hour to convert.  I don't know if it is a conscious decision or accident - but I do know it is a Good Thing!

 

Very Best Wishes,

[Colin parks]

.. Hmm, you had me in a sweat for a second with the last comment...

 

I seem to recall you saying you were happy with your BIL - sounds now like you are ready to think again!!  New shoe fuses, that will show up the equipment fuses...... where next???

 

But I have to say that - speaking generally - "modern" RTR stock does increasingly seem to be made with wider gauges in mind - as an example, I have a Hornby "Schools" half done, and in the case of the tender, the frames were quite wide enough to allow a wheel swap. And my Heljan BRCW / Crompton Type 3 took all of half an hour to convert.  I don't know if it is a conscious decision or accident - but I do know it is a Good Thing!

 

Very Best Wishes,

Hi Howard,

 

Well changing the shoe fuses on the 2 BIL would not be the end of the world, I have already eradicated the Hornby equipment fuses on mine.

 

Despite the gripes, we have to glad that we have so many models to choose from these days. It is just sometimes that you wonder why certain parts could not have been made better, but I suppose the challenge is part of the fun. Good news about the Heljan class 33 being so easy to covert too.

 

All the best,

 

Colin