Anyone want cheap motor gearbox units?

[Peaky 556]

Hello all, I've been of a mind lately to develop and market some high-quality, small axle hung motor gearbox units, along the lines of this Slaters unit that is very convenient to fit:


The only difference is that it would be much better value ! 😎

Two designs could be offered:
Lower speed one typically for DMUs with 1/4" axles, powered with 10-12 cells.
Higher power one to suit mainline express diesel-electrics with 8mm axles, using 12V SLA battery

The question is, what sort of uptake is possible? 

Regards, Tim

[Peaky 556]

That Slaters unit is for G1 by the way, I don't think anyone offers anything like this in Gauge 3 (yet!).

[cabbage]

Tim,
I would say that you use 6mm not 1/4 inch. This improves the number of gears available.

Regards

Ralph

[Doddy]

Hello Tim,

Without sounding negative, GRS which was the pre-eminent supplier of diesels for G3 have long stopped the sale of their Class 08 shunter and never even finished the development of their Class 20 due to lack of interest.

Luckily the Class 121 DMU and the GWR Railcar is still available, but then how many people modelling in G3 have over £800 to buy one?

The G3 Peak design, has only five or six (less the late Dave Lowe) builders as far as I am aware, with only 22 odd sets of Peak construction drawings sold. Until there is a growing demand for G3 diesels, I can't see the demand for many G3 scale motor gearboxes at this moment in time.

Recently there has been postings on 3D printed G3 diesels such as the privately built Class 08/09, but much more development within Gauge One where 3D resin printed models of Class 37's, Class 55 Deltics and Class 68's have all appeared on Youtube or at large scale diesel events. When ticketsonline get their act together then maybe well see the re-introduction of brass G1 diesel kits for Classes, 08, 20, 37, 40, 45, 47, 50, 52, 55 and 59. ( And no they do not have the artwork to blow them up to G3 scale - I asked!)

Even 5" is getting in on the 3D printing scene with the new Class 37 from Pheonix . And I am also aware of a very accurate 5" gauge Carbon Fibre Class 52 Western being developed for sale.
Bob

Ref:
http://www.grsuk.com/BR-CLASS121-RAILCAR-M2940
http://www.grsuk.com/GWR-Railcar-Flying-Banana-Kit-M2626

[Doddy]

Tim,
I would say that you use 6mm not 1/4 inch. This improves the number of gears available.

Regards

Ralph

Hmn! 1/4" lets you use Slaters G3 wheels off the shelf though. 

[keith Bristol]

Hi Tim,

Count me in for the axle hung motors, I need to re bogie my dmus and I have the need for bogies for 2nr class 20, a 25 and 2nr class 58...

Doddy, I'll reply re Gloucester bogie shortly and watch this space for 20.
Keith

[Peaky 556]

Hmn! 1/4" lets you use Slaters G3 wheels off the shelf though. 

Thanks for pointing this out Doddy, it's exactly the reason for choosing 1/4" axles for the DMU and similar types. 😎

On the aspect of a small market, I can largely agree with you, but there is always the chance that some scratchbuilding will be initiated by availability of mechanical bits!  It's worth emphasising that I'm needing these units for myself, so if I can build a bigger batch then it might reduce unit costs slightly.

Best regards, Tim

[MikeWilliams]

Sorry Tim, not my era of interest.  But, I really hope you go ahead with these as I am sure their availability will generate the interest.  People are much more likely to buy one when they see it, than those on the forum who are planning ahead.

As for the comparison with G1 - I don't see the relevance myself.

So, please go for it, but sorry I don't want one!

Mike

[Doddy]

As for the comparison with G1 - I don't see the relevance myself.

Mike

The relevance is that G3 is a minority interest and does not have products being developed for the requirement of having a motor gearbox put on the market unlike G1 which does, I thought that was obvious given the length of the products I listed for G1 vs G3. Perhaps others don't see the link?

[MikeWilliams]

OK Doddy, probably I didn't explain myself very well!

What I meant was, are you saying that although there is a growing market for G1 diesels there is no market for a G3 gearbox like this because the G3 kits are not there?

If so, then I guess it depends on expectations and production runs.  I work on low production runs and amortise the costs over ten or twenty kits.  Some have never broken even, whereas others have and it is impossible to predict which will!  I also don't make a living out of model railways and don't even need to make a profit.  If that is the case for Tim, then he may not need the large market that a G1 manufacturer like Slaters would.

Mike

[Peaky 556]

Hi Tim,
Count me in for the axle hung motors, I need to re bogie my dmus and I have the need for bogies for 2nr class 20, a 25 and 2nr class 58

Hi Keith, thanks for the interest.  Can I just ask you to give the wheel sizes of those models you list, and required top speeds, to save me doing the research?  I'd just like to add these design requirements into the mix.

On the model availability front, there are some deep thoughts happening with one of our members on possibly producing kits for a couple of DMUs.  I'll not say any more on the subject, as I suspect it's more medium than short-term.

Thanks, Tim

[John Candy]

Tim,
The only diesel I have at present is a GWR "Flying Banana" which has been part built for at least 10 years!
As I mentioned about 4 years ago, on this forum, LMS 10000 is a long-term objective as a kit successor to the Sentinel.
If (bearing in mind I currently have 9 steam locos in various stages of planning and construction ... and that excludes 4 others being built by Mike Danby) I get around to it before they carry me out, then your units would come in useful.
Regards,
John.

[Doddy]

Yes Mike,

I would tend to agree and opinion to say that if more G3 kits were available then maybe the G3 axle-hung motor requirement would go up. As a backstop. From his off-line correspondance I think Tim wants to re-work his G3 design into a smaller form to fit G1 as well, but obviously not with exactly the same components.

As for train speed Tim. Keith has outlined the following. 1st Generation DMU, Class 08, Class 20, Class 25, and Class 58 but also has a Class 73.
The maximum speeds of which are:-

   
• Class 08 15 mph or 20 mph
• Class 09 27.5 mph
• Class 20 75 mph
• Class 25 90 mph
• Class 58 80 mph
• Class 73/0 80 mph, Class 73/1 90 mph
• 1st Gen DMU 70 mph

The Ian Allan combined stock books can be readily purchased from eBay at reasonable prices, many of which are not yet in an underlined state of condition. The content of these volumes has an enormous amount of technial specifications that are rarely found online and readily dispel incorrect information via Wikipedia (aka the Class 44 maximum speed of 75mph  )



Given the modelling that is going on behind the scenes, the following info may also be useful.

   
• GWR Diesel Railcar Nos 1 to 4 63 mph
• GWR Diesel Railcar Nos 5 to 18 80 mph
• Class 44, 45, 46 90 mph
• Blue Pullman 90 mph
• London Transports networks maximum speed limit is 45 mph

The class 20 and 58 may be intended for HAA hopper haulage in which case those wagons operational limits were initially 40-45mph rising to 60mph with HAA hopper modifications.

Principle O gauge suppliers of motor bogie kits tend to offer two options, maximum speed for express passenger trains and a slower option for mixed goods traffic, in which diesels running at the end of BR steam days would be rather slow with unfitted goods trains. 30-40mph?
I should mention that there are obviously Steam orientated Ian Allan combined volumes as well. 




FYI - Tim.

For further reading I have enclosed a table of common (15) different wheel diameters for various Diesel and Electric classes of locomotives, and 1st generation DMUs and EMUs.

Bob

[Peaky 556]

Thanks to all for the encouraging remarks, and especially to Doddy for the huge amount of research done.

Can I ask though, aimed at Keith and John initially but also to anyone else who might be interested, to tell me what wheel diameters and maximum speeds they would wish to run at?  This is a way of understanding the gear ratios I might need, which is essential in my view if I am going to offer a couple of standard designs that would suit most applications in G3?

Regards, Tim

[John Candy]

Tim,

LMS 10000 (also applies to BR 10001) : Wheel diameter 3ft 6 ins;  motors were capable of 935rpm but were governed to 750 rpm giving a max. speed of 93mph.

GWR Gloucester RCW/ AEC railcars ("Flying Bananas" Nos. 5 to 17) : Wheel diameter  3ft 1 inch;                                                               max. speed of 80mph.

For purposes of a model, I would limit speeds to scale 60mph for my purposes.

John.