Banana Bogies

[Peaky 556]

Can anyone tell me the correct wheelbase for the GWR bogies, of the model produced by GRS?  Oh, and wheel diameter too?
I'm contemplating a sample production of bogies to suit, as I believe those supplied by GRS were less than ideal.

[Chris_P]

Internet forums are often useful https://www.national-preservation.com/threads/gwr-rail-cars.1196673/ provides many pictures of the various types as I'm not sure which GRS followed these may help identify the correct prototype.  Meanwhile a few posts down on the first page of https://www.rmweb.co.uk/community/index.php?/topic/15724-ks-gwr-railcar-restoration-and-lambourn-kit-build/ is a drawing showing 7 foot wheelbase and further down the suggestion is a 3ft 2inch wheel size.  It is also apparent that there are various designs with internet searches providing a number of good detailed photographs.

Good luck with your project.

[cabbage]

I think it was a modified "USA Trains" power brick. Thomas might be a better source of info than us(?)

Regards

Ralph

[Doddy]

The GRS model looks to be one of the 70 seater versions, numbers 5 to 9 and 13 to 16.

   
• Railcars 1 to 4
• Wheelbase 7'
• Wheel Diameter 37"
• Max MPH = 63

   
• Railcars 5 to 17
• Wheelbase 7'
• Wheel Diameter 37"
  
• Max MPH = 80

   
• Railcar 18
• Wheelbase 8' 6"
• Wheel Diameter 38"
• Max MPH = 80

   
• Railcars 19 to 38
• Wheelbase 8' 6"
• Wheel Diameter 38"
• Max MPH - 70

[Doddy]

I think it was a modified "USA Trains" power brick. Thomas might be a better source of info than us(?)

Regards

Ralph

Yes the bogie is a modified USA Trains 'brick' motor block with extended axles and no pickups. The motor block used is the Long - 94.5mm wheelbase (from USA Trains GP7, GP9, GP30 and GP38-2 locomotives) NB: 7' = 94.407mm in Gauge 3

[John Candy]

I have just measured the cosmetic frame castings (not used on my model which retains its "skirts") and the centres are 96.5mm...... which is very marginally over the correct 7ft.
Incidentally, the original ten kits (of which mine is one) were supplied with Aristocraft power bogies.

John.

[Peaky 556]

Thank you very much all.  The concensus seems to be 7 feet wheelbase for the prototype, which is fairly accurately modelled by some of the GRS models.  I say 'some' because, intriguingly, my client has whitemetal bogie sides in his GRS kit that measure 100mm centres.  Maybe it's another sort of motor block, and so I have a quandary in making either to the correct prototype dimensions (always a first choice), or alternatively making up to suit some parts in the kit and possibly perpetuating an error (possibly the pragmatic solution).  🤔

[Doddy]

I have just measured the cosmetic frame castings (not used on my model which retains its "skirts") and the centres are 96.5mm...... which is very marginally over the correct 7ft.
Incidentally, the original ten kits (of which mine is one) were supplied with Aristocraft power bogies.

John.

Yes, Micheal (GRS) said that the Aristo-Craft blocks went out of gauge and also stripped the gears. My Railcar blocks are the USA Trains version.

[Doddy]

so I have a quandary in making either to the correct prototype dimensions (always a first choice), or alternatively making up to suit some parts in the kit and possibly perpetuating an error (possibly the pragmatic solution).  🤔

Easily answered . . .   Your clients 100mm bogie sideframes are the 1st choice - presuming you are not developing a new set of sideframes?

If there are different variations of sideframes then GRS will know, perhaps a collaboration between the two of you will bring out the facts?

[John Candy]

If my model should require a refit, a couple of mm will not bother me because of the "skirts" concealing almost the entire running gear.

HOWEVER, in view of the different types of power unit involved, a major concern would be the arrangement of the bogie mountings.  Are the mountings in the floor of the kit at the same centres in all versions?
So far as I am aware the kit evolved as follows:
Version "1" .... Separate sides/ends/roof/floor with Aristocraft units.
Version "2" ..... similar to "1" but with USA Trains units.
Version"3" ... Unitary body casting with separate floor and USA Trains units.

The floor in Version "3" is very different to that in "1" (I rebuilt Mark Thatcher's example last year).

John.

[hornbeam]

   So I must confess I'm the cause of all of this. I acquired an early example of one of these a few years ago. To be polite it was not built well but the price was right! Mark Pretious is converting the body into the parcels version so my attention turned to the bogies. One was without motor, the other sounded rough.
    Having measured the side frames they are indeed 96.5mm so as you say John close to the correct wheelbase. I have one of the later versions of the kit purchased this year. This has the later USA trains bogies and plastic floor not the resin floor of the early kits. I suspect I will have to pack out the bogie mount with the bogies Tim produces.

  Regards,

Simon.

[Doddy]

Hello Simon. Hello Tim, et al

Parcels version? - It's Railcar No# 34 then! 

   
• Railcars 19 to 38
• Wheelbase 8' 6"
• Wheel Diameter 38"
• Max MPH - 70

Who is really that bothered with a 3/4" difference in the GRS wheelbase length vs the prototype, unless Tim is creating an entirely new scale 8' 6" bogie sideframe for your model? It never appeared to have made any difference to the reception of LIMA and Hornbys models.
I really look forward to seeing the completed model - kudos for creating something unique Simon.  *****

[AllWight]

[AllWight]

[AllWight]

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