7mm: A Tale of Two 40s

[Dog Star]

Here are some detail shots of D200 which was in the NRM tent yesterday. The photos are posted in the order RH end to LH end - however, I have no idea as to which side is shown here. Of possible interest... some signs / labels are missing judging by the pairs of screw holes.




























regards, Graham

 

[Dikitriki]

Thank you Graham, that's very thoughtful of you.

It's the location of those fittings from an underneath angle that is almost impossible to find, so tremendously useful. Though I must profess myself to be alarmed at the lack of clearance between fitting and bogie frame. I may have to give mine a wee it more room!

Yours

Richard

 

[Dog Star]

... I must profess myself to be alarmed at the lack of clearance between fitting and bogie frame.

There are several places along the underframe where there is "zero" clearance - I was surprised to see that the engine body appears to sit direct onto the bogie frames. At either end there are "circular" covers to a sliding surface / transom and that surface takes the weight through, probably, a bronze bush. The covers are rubber and one had perished to reveal the slide and the bush.

 

[mickoo]

Areas in red are covers for the four bearing pads on all 1+c0-co+1 bogies, they do not form a circular radius but are two differing radii, fore and aft are one and left and right another.



This is your primary suspension, I.E. zero, Class 40 and Peak bogies do not tilt fore and aft or left and right, hence their banning from the humps in marshalling yards.

 

[Cliff Williams]

If this helps at all in the comparison, here are a couple of shots of D395 that I made for a customer.
The next one will have flush glazing cut by me, now I have developed a good, but laborious, method!

 

[40126]

Steve

 

[iploffy]

If this helps at all in the comparison, here are a couple of shots of D395 that I made for a customer.
The next one will have flush glazing cut by me, now I have developed a good, but laborious, method!

View attachment 26303View attachment 26304

Cliff can you tell me how you managed to stop the front pony wheels springing pushing up the driving wheels pls

 

[mickoo]

If this helps at all in the comparison, here are a couple of shots of D395 that I made for a customer.
The next one will have flush glazing cut by me, now I have developed a good, but laborious, method!

View attachment 26303View attachment 26304

I like the cab lighting, just the right colour, one thing I never seen modelled is the engine room lighting, a must for my JLTRT model, though it will need the resin grills removed and see through slotted ones adding, no frost grills either!.



Copyright exists with original owners, show here for indicative purposes only.

 

[alcazar]

Will you be showing some representation of the engine room interior?

 

[Cliff Williams]

iploffy I have braced the inside of the 40 bogies with brass stretchers for strength, the weak point is the central bogie pivot - by doing this it allowed me to weight the loco for super haulage, this also assists with the bogie springing that is causing you a headache. You also have to fit a form of springing on the centre axle, this is easy, I will need to find the pic for that for you. Also I feel for DCC it is not safe to have bolts holding the bogie pivot in place, it just takes something to slacken off and you have a perfect jumper from one wheel to the other and it could harm the chip!

 

[mickoo]

Will you be showing some representation of the engine room interior?

Yes, it'll need a radiator section at least through the grills.

 

[Dikitriki]

Hi Folks

Not much happening while my model room is being rebuilt, but just thinking out loud....

Are the springs/axlebox covers/hangers/mounts etc on a 40 identical to those on a Peak?

I'm having further thoughts about the plastic card bogie, and considering a Mickoo/JLTRT combo

Cheers

Richard

 

[iploffy]

Yes Richard the only real difference being a cut out on the bogies on the 40's behind the buffer beam in both sides of the side plate I think it was something to do with weight

 

[mickoo]

Hi Folks

Not much happening while my model room is being rebuilt, but just thinking out loud....

Are the springs/axlebox covers/hangers/mounts etc on a 40 identical to those on a Peak?

I'm having further thoughts about the plastic card bogie, and considering a Mickoo/JLTRT combo

Cheers

Richard

Peaks and Whistlers have the same axleboxes and springs/fittings as near as can be determined, if you can get a set of castings from JLTRT from their Peak kits then your going to get a head start, the Class 40 has the springs and axleboxes moulded on, the Peak is/was still a brass bogie.....wish they had done that with the 40 kit TBH, much more fidelity.

 

[mickoo]

Yes Richard the only real difference being a cut out on the bogies on the 40's behind the buffer beam in both sides of the side plate I think it was something to do with weight

Not so, the plate work is slightly different between the two classes. The oval hole was not present on the first ten but was cut out later, but at least two or three bogies lasted the full service life with out cut outs, two became snow ploughs and one was last seen under D366 at Crewe Works where she was scrapped due to extensive damage, general consensus is that all had cut outs by mid 61, recent detailed research has show this may not be the case.

Source suggest the cut out is for lubrication access to the pony truck swing links? Doubt it's for weight saving as those few bits of metal probably didn't amount to more than 200kg in weight saving. In later life some water tanked locos ran with full water tanks to get better adhesion as fuel ran low and locos with tanks removed may have had concrete inserted as a replacement weight to keep adhesion up, though I've no proof of that in class 40 but some other classes had that done.

The buffer beams also differ in details and plate work, they are close but not the same as far I've been able to ascertain.

 

[Steph Dale]

The difference between the classes is related to the Southern trio, as far as I can make out.
All had their mechanical equipment built by the SR, but to EE designs. Remembering the EE design was already worked out for their export locos it emerged as detail differences; the bolsterless pivot design (pure Bulleid) latter being incorporated in both EE and BR designs to allow clearance around the middle traction motor.
And so there was minor design deviation from the outset; the EE design supporting only EE equipment, the BR design being rather more 'supplier agnostic'.
Steph